Merge WebKit at r84325: Initial merge by git.

Change-Id: Ic1a909300ecc0a13ddc6b4e784371d2ac6e3d59b

11 files changed, 235 insertions, 104 deletions

diff --git a/Source/WebCore/platform/graphics/gpu/BicubicShader.cpp b/Source/WebCore/platform/graphics/gpu/BicubicShader.cpp
index 40c9843..f6f428d 100644
--- a/Source/WebCore/platform/graphics/gpu/BicubicShader.cpp
+++ b/Source/WebCore/platform/graphics/gpu/BicubicShader.cpp
@@ -55,11 +55,12 @@ PassOwnPtr<BicubicShader> BicubicShader::create(GraphicsContext3D* context)
     static const char* vertexShaderSource =
         "uniform mat3 matrix;\n"
         "uniform mat3 texMatrix;\n"
-        "attribute vec3 position;\n"
+        "attribute vec2 position;\n"
         "varying vec2 texCoord;\n"
         "void main() {\n"
-        "    texCoord = (texMatrix * position).xy;\n"
-        "    gl_Position = vec4(matrix * position, 1.0);\n"
+        "    vec3 pos = vec3(position, 1.0);\n"
+        "    texCoord = (texMatrix * pos).xy;\n"
+        "    gl_Position = vec4(matrix * pos, 1.0);\n"
         "}\n";
     static const char* fragmentShaderSource =
         "#ifdef GL_ES\n"
@@ -127,7 +128,7 @@ void BicubicShader::use(const AffineTransform& transform, const AffineTransform&
     m_context->uniform1i(m_imageLocation, 0);
     m_context->uniform1f(m_alphaLocation, alpha);
 
-    m_context->vertexAttribPointer(m_positionLocation, 3, GraphicsContext3D::FLOAT, false, 0, 0);
+    m_context->vertexAttribPointer(m_positionLocation, 2, GraphicsContext3D::FLOAT, false, 0, 0);
 
     m_context->enableVertexAttribArray(m_positionLocation);
 }
diff --git a/Source/WebCore/platform/graphics/gpu/ConvolutionShader.cpp b/Source/WebCore/platform/graphics/gpu/ConvolutionShader.cpp
index f0b6bd9..b11d966 100644
--- a/Source/WebCore/platform/graphics/gpu/ConvolutionShader.cpp
+++ b/Source/WebCore/platform/graphics/gpu/ConvolutionShader.cpp
@@ -58,13 +58,14 @@ PassOwnPtr<ConvolutionShader> ConvolutionShader::create(GraphicsContext3D* conte
         "uniform mat3 matrix;\n"
         "uniform mat3 texMatrix;\n"
         "uniform vec2 imageIncrement;\n"
-        "attribute vec3 position;\n"
+        "attribute vec2 position;\n"
         "varying vec2 imageCoord;\n"
         "void main() {\n"
+        "    vec3 pos = vec3(position, 1.0);\n"
         "    // Offset image coords by half of kernel width, in image texels\n"
-        "    gl_Position = vec4(matrix * position, 1.0);\n"
+        "    gl_Position = vec4(matrix * pos, 1.0);\n"
         "    float scale = (float(KERNEL_WIDTH) - 1.0) / 2.0;\n"
-        "    imageCoord = (texMatrix * position).xy - vec2(scale, scale) * imageIncrement;\n"
+        "    imageCoord = (texMatrix * pos).xy - vec2(scale, scale) * imageIncrement;\n"
         "}\n";
     char vertexShaderSource[1024];
     snprintf(vertexShaderSource, sizeof(vertexShaderSource), vertexShaderRaw, kernelWidth);
@@ -115,7 +116,7 @@ void ConvolutionShader::use(const AffineTransform& transform, const AffineTransf
         kernelWidth = m_kernelWidth;
     m_context->uniform1fv(m_kernelLocation, const_cast<float*>(kernel), kernelWidth);
 
-    m_context->vertexAttribPointer(m_positionLocation, 3, GraphicsContext3D::FLOAT, false, 0, 0);
+    m_context->vertexAttribPointer(m_positionLocation, 2, GraphicsContext3D::FLOAT, false, 0, 0);
 
     m_context->enableVertexAttribArray(m_positionLocation);
 }
diff --git a/Source/WebCore/platform/graphics/gpu/DrawingBuffer.cpp b/Source/WebCore/platform/graphics/gpu/DrawingBuffer.cpp
index 2a83fcf..8e293f7 100644
--- a/Source/WebCore/platform/graphics/gpu/DrawingBuffer.cpp
+++ b/Source/WebCore/platform/graphics/gpu/DrawingBuffer.cpp
@@ -144,112 +144,128 @@ void DrawingBuffer::resizeDepthStencil(int sampleCount)
     m_context->bindRenderbuffer(GraphicsContext3D::RENDERBUFFER, 0);
 }
 
-void DrawingBuffer::reset(const IntSize& newSize)
+void DrawingBuffer::clearFramebuffer()
 {
-    m_size = newSize;
+    m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_multisampleFBO ? m_multisampleFBO : m_fbo);
+    const GraphicsContext3D::Attributes& attributes = m_context->getContextAttributes();
+    float clearDepth = 0;
+    int clearStencil = 0;
+    unsigned char depthMask = false;
+    unsigned int stencilMask = 0xffffffff;
+    unsigned char isScissorEnabled = false;
+    unsigned long clearMask = GraphicsContext3D::COLOR_BUFFER_BIT;
+    if (attributes.depth) {
+        m_context->getFloatv(GraphicsContext3D::DEPTH_CLEAR_VALUE, &clearDepth);
+        m_context->clearDepth(1);
+        m_context->getBooleanv(GraphicsContext3D::DEPTH_WRITEMASK, &depthMask);
+        m_context->depthMask(true);
+        clearMask |= GraphicsContext3D::DEPTH_BUFFER_BIT;
+    }
+    if (attributes.stencil) {
+        m_context->getIntegerv(GraphicsContext3D::STENCIL_CLEAR_VALUE, &clearStencil);
+        m_context->clearStencil(0);
+        m_context->getIntegerv(GraphicsContext3D::STENCIL_WRITEMASK, reinterpret_cast<int*>(&stencilMask));
+        m_context->stencilMaskSeparate(GraphicsContext3D::FRONT, 0xffffffff);
+        clearMask |= GraphicsContext3D::STENCIL_BUFFER_BIT;
+    }
+    isScissorEnabled = m_context->isEnabled(GraphicsContext3D::SCISSOR_TEST);
+    m_context->disable(GraphicsContext3D::SCISSOR_TEST);
+
+    float clearColor[4];
+    m_context->getFloatv(GraphicsContext3D::COLOR_CLEAR_VALUE, clearColor);
+    m_context->clearColor(0, 0, 0, 0);
+    m_context->clear(clearMask);
+    m_context->clearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
+
+    if (attributes.depth) {
+        m_context->clearDepth(clearDepth);
+        m_context->depthMask(depthMask);
+    }
+    if (attributes.stencil) {
+        m_context->clearStencil(clearStencil);
+        m_context->stencilMaskSeparate(GraphicsContext3D::FRONT, stencilMask);
+    }
+    if (isScissorEnabled)
+        m_context->enable(GraphicsContext3D::SCISSOR_TEST);
+    else
+        m_context->disable(GraphicsContext3D::SCISSOR_TEST);
+}
 
+bool DrawingBuffer::reset(const IntSize& newSize)
+{
     if (!m_context)
-        return;
-        
+        return false;
+
     m_context->makeContextCurrent();
-    
-    const GraphicsContext3D::Attributes& attributes = m_context->getContextAttributes();
-    unsigned long internalColorFormat, colorFormat, internalRenderbufferFormat;
-    if (attributes.alpha) {
-        internalColorFormat = GraphicsContext3D::RGBA;
-        colorFormat = GraphicsContext3D::RGBA;
-        internalRenderbufferFormat = Extensions3D::RGBA8_OES;
-    } else {
-        internalColorFormat = GraphicsContext3D::RGB;
-        colorFormat = GraphicsContext3D::RGB;
-        internalRenderbufferFormat = Extensions3D::RGB8_OES;
-    }
 
+    int maxTextureSize = 0;
+    m_context->getIntegerv(GraphicsContext3D::MAX_TEXTURE_SIZE, &maxTextureSize);
+    if (newSize.height() > maxTextureSize || newSize.width() > maxTextureSize) {
+      clear();
+      return false;
+    }
 
-    // resize multisample FBO
-    if (multisample()) {
-        int maxSampleCount = 0;
-        
-        m_context->getIntegerv(Extensions3D::MAX_SAMPLES, &maxSampleCount);
-        int sampleCount = std::min(8, maxSampleCount);
+    const GraphicsContext3D::Attributes& attributes = m_context->getContextAttributes();
 
-        m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_multisampleFBO);
+    if (newSize != m_size) {
+        m_size = newSize;
 
-        m_context->bindRenderbuffer(GraphicsContext3D::RENDERBUFFER, m_multisampleColorBuffer);
-        m_context->getExtensions()->renderbufferStorageMultisample(GraphicsContext3D::RENDERBUFFER, sampleCount, internalRenderbufferFormat, m_size.width(), m_size.height());
-        m_context->framebufferRenderbuffer(GraphicsContext3D::FRAMEBUFFER, GraphicsContext3D::COLOR_ATTACHMENT0, GraphicsContext3D::RENDERBUFFER, m_multisampleColorBuffer);
-        resizeDepthStencil(sampleCount);
-        if (m_context->checkFramebufferStatus(GraphicsContext3D::FRAMEBUFFER) != GraphicsContext3D::FRAMEBUFFER_COMPLETE) {
-            // Cleanup
-            clear();
-            return;
+        unsigned long internalColorFormat, colorFormat, internalRenderbufferFormat;
+        if (attributes.alpha) {
+            internalColorFormat = GraphicsContext3D::RGBA;
+            colorFormat = GraphicsContext3D::RGBA;
+            internalRenderbufferFormat = Extensions3D::RGBA8_OES;
+        } else {
+            internalColorFormat = GraphicsContext3D::RGB;
+            colorFormat = GraphicsContext3D::RGB;
+            internalRenderbufferFormat = Extensions3D::RGB8_OES;
         }
-    }
 
-    // resize regular FBO
-    m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_fbo);
 
-    m_context->bindTexture(GraphicsContext3D::TEXTURE_2D, m_colorBuffer);
-    m_context->texImage2DResourceSafe(GraphicsContext3D::TEXTURE_2D, 0, internalColorFormat, m_size.width(), m_size.height(), 0, colorFormat, GraphicsContext3D::UNSIGNED_BYTE);
-    m_context->framebufferTexture2D(GraphicsContext3D::FRAMEBUFFER, GraphicsContext3D::COLOR_ATTACHMENT0, GraphicsContext3D::TEXTURE_2D, m_colorBuffer, 0);
-    m_context->bindTexture(GraphicsContext3D::TEXTURE_2D, 0);
-    if (!multisample())
-        resizeDepthStencil(0);
-    if (m_context->checkFramebufferStatus(GraphicsContext3D::FRAMEBUFFER) != GraphicsContext3D::FRAMEBUFFER_COMPLETE) {
-        // Cleanup
-        clear();
-        return;
-    }
+        // resize multisample FBO
+        if (multisample()) {
+            int maxSampleCount = 0;
+            
+            m_context->getIntegerv(Extensions3D::MAX_SAMPLES, &maxSampleCount);
+            int sampleCount = std::min(8, maxSampleCount);
 
-    if (multisample())
-        m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_multisampleFBO);
+            m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_multisampleFBO);
 
-    if (!m_context->getExtensions()->supports("GL_CHROMIUM_resource_safe")) {
-        // Initialize renderbuffers (depth/stencil).
-        float clearDepth = 0;
-        int clearStencil = 0;
-        unsigned char depthMask = true;
-        unsigned int stencilMask = 0xffffffff;
-        unsigned char isScissorEnabled = false;
-        unsigned long clearMask = 0;
-        if (attributes.depth) {
-            m_context->getFloatv(GraphicsContext3D::DEPTH_CLEAR_VALUE, &clearDepth);
-            m_context->clearDepth(1);
-            m_context->getBooleanv(GraphicsContext3D::DEPTH_WRITEMASK, &depthMask);
-            m_context->depthMask(true);
-            clearMask |= GraphicsContext3D::DEPTH_BUFFER_BIT;
-        }
-        if (attributes.stencil) {
-            m_context->getIntegerv(GraphicsContext3D::STENCIL_CLEAR_VALUE, &clearStencil);
-            m_context->clearStencil(0);
-            m_context->getIntegerv(GraphicsContext3D::STENCIL_WRITEMASK, reinterpret_cast<int*>(&stencilMask));
-            m_context->stencilMaskSeparate(GraphicsContext3D::FRONT, 0xffffffff);
-            clearMask |= GraphicsContext3D::STENCIL_BUFFER_BIT;
+            m_context->bindRenderbuffer(GraphicsContext3D::RENDERBUFFER, m_multisampleColorBuffer);
+            m_context->getExtensions()->renderbufferStorageMultisample(GraphicsContext3D::RENDERBUFFER, sampleCount, internalRenderbufferFormat, m_size.width(), m_size.height());
+            m_context->framebufferRenderbuffer(GraphicsContext3D::FRAMEBUFFER, GraphicsContext3D::COLOR_ATTACHMENT0, GraphicsContext3D::RENDERBUFFER, m_multisampleColorBuffer);
+            resizeDepthStencil(sampleCount);
+            if (m_context->checkFramebufferStatus(GraphicsContext3D::FRAMEBUFFER) != GraphicsContext3D::FRAMEBUFFER_COMPLETE) {
+                // Cleanup
+                clear();
+                return false;
+            }
         }
-        if (clearMask) {
-            isScissorEnabled = m_context->isEnabled(GraphicsContext3D::SCISSOR_TEST);
-            m_context->disable(GraphicsContext3D::SCISSOR_TEST);
 
-            m_context->clear(clearMask);
+        // resize regular FBO
+        m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_fbo);
 
-            if (attributes.depth) {
-                m_context->clearDepth(clearDepth);
-                m_context->depthMask(depthMask);
-            }
-            if (attributes.stencil) {
-                m_context->clearStencil(clearStencil);
-                m_context->stencilMaskSeparate(GraphicsContext3D::FRONT, stencilMask);
-            }
-            if (isScissorEnabled)
-                m_context->enable(GraphicsContext3D::SCISSOR_TEST);
-            else
-                m_context->disable(GraphicsContext3D::SCISSOR_TEST);
+        m_context->bindTexture(GraphicsContext3D::TEXTURE_2D, m_colorBuffer);
+        
+        m_context->texImage2DResourceSafe(GraphicsContext3D::TEXTURE_2D, 0, internalColorFormat, m_size.width(), m_size.height(), 0, colorFormat, GraphicsContext3D::UNSIGNED_BYTE);
+
+        m_context->framebufferTexture2D(GraphicsContext3D::FRAMEBUFFER, GraphicsContext3D::COLOR_ATTACHMENT0, GraphicsContext3D::TEXTURE_2D, m_colorBuffer, 0);
+        m_context->bindTexture(GraphicsContext3D::TEXTURE_2D, 0);
+
+        if (!multisample())
+            resizeDepthStencil(0);
+        if (m_context->checkFramebufferStatus(GraphicsContext3D::FRAMEBUFFER) != GraphicsContext3D::FRAMEBUFFER_COMPLETE) {
+            // Cleanup
+            clear();
+            return false;
         }
     }
 
-    m_context->flush();
-    
+    clearFramebuffer();
+
     didReset();
+
+    return true;
 }
 
 void DrawingBuffer::commit(long x, long y, long width, long height)
diff --git a/Source/WebCore/platform/graphics/gpu/DrawingBuffer.h b/Source/WebCore/platform/graphics/gpu/DrawingBuffer.h
index 606484e..caf3aa5 100644
--- a/Source/WebCore/platform/graphics/gpu/DrawingBuffer.h
+++ b/Source/WebCore/platform/graphics/gpu/DrawingBuffer.h
@@ -44,6 +44,7 @@
 
 #if ENABLE(SKIA_GPU)
 class GrContext;
+struct GrPlatformSurfaceDesc;
 #endif
 
 namespace WebCore {
@@ -60,7 +61,10 @@ public:
     
     ~DrawingBuffer();
 
-    void reset(const IntSize&);
+    void clearFramebuffer();
+
+    // Returns true if the buffer was successfully resized.
+    bool reset(const IntSize&);
     void bind();
     IntSize size() const { return m_size; }
     Platform3DObject colorBuffer() const { return m_colorBuffer; }
@@ -101,6 +105,7 @@ public:
 
 #if ENABLE(SKIA_GPU)
     void setGrContext(GrContext* ctx);
+    void getGrPlatformSurfaceDesc(GrPlatformSurfaceDesc*);
 #endif
 
     PassRefPtr<GraphicsContext3D> graphicsContext3D() const { return m_context; }
diff --git a/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.cpp b/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.cpp
index 5b155a5..b228cbf 100644
--- a/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.cpp
+++ b/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.cpp
@@ -562,6 +562,108 @@ int numXRayCrossingsForCubic(const XRay& xRay, const FloatPoint cubic[4], bool&
     return numCrossings;
 }
 
+/*
+ * Based on C code from the article
+ * "Testing the Convexity of a Polygon"
+ * by Peter Schorn and Frederick Fisher,
+ * (schorn@inf.ethz.ch, fred@kpc.com)
+ * in "Graphics Gems IV", Academic Press, 1994
+ */
+
+static inline int convexCompare(const FloatSize& delta)
+{
+    return (delta.width() > 0) ? -1 : /* x coord diff, second pt > first pt */
+           (delta.width() < 0) ?  1 : /* x coord diff, second pt < first pt */
+           (delta.height() > 0) ? -1 : /* x coord same, second pt > first pt */
+           (delta.height() < 0) ?  1 : /* x coord same, second pt > first pt */
+           0; /* second pt equals first point */
+}
+
+static inline float convexCross(const FloatSize& p, const FloatSize& q)
+{
+    return p.width() * q.height() - p.height() * q.width();
+}
+
+static inline bool convexCheckTriple(const FloatSize& dcur, const FloatSize& dprev, int* curDir, int* dirChanges, int* angleSign)
+{
+    int thisDir = convexCompare(dcur);
+    if (thisDir == -*curDir)
+        ++*dirChanges;
+    *curDir = thisDir;
+    float cross = convexCross(dprev, dcur);
+    if (cross > 0) {
+        if (*angleSign == -1)
+            return false;
+        *angleSign = 1;
+    } else if (cross < 0) {
+        if (*angleSign == 1)
+            return false;
+        *angleSign = -1;
+    }
+    return true;
+}
+
+bool isConvex(const FloatPoint* vertices, int nVertices)
+{
+    int dirChanges = 0, angleSign = 0;
+    FloatPoint second, third;
+    FloatSize dprev, dcur;
+
+    /* Get different point, return if less than 3 diff points. */
+    if (nVertices < 3)
+        return false;
+    int i = 1;
+    while (true) {
+        second = vertices[i++];
+        dprev = second - vertices[0];
+        if (dprev.width() || dprev.height())
+            break;
+        /* Check if out of points. Check here to avoid slowing down cases
+         * without repeated points.
+         */
+        if (i >= nVertices)
+            return false;
+    }
+    FloatPoint saveSecond = second;
+    int curDir = convexCompare(dprev);        /* Find initial direction */
+    while (i < nVertices) {
+        /* Get different point, break if no more points */
+        third = vertices[i++];
+        dcur = third - second;
+        if (!dcur.width() && !dcur.height())
+            continue;
+
+        /* Check current three points */
+        if (!convexCheckTriple(dcur, dprev, &curDir, &dirChanges, &angleSign)) 
+            return false;
+        second = third;     /* Remember ptr to current point. */
+        dprev = dcur;       /* Remember current delta. */
+    }
+
+    /* Must check for direction changes from last vertex back to first */
+    third = vertices[0];                  /* Prepare for 'ConvexCheckTriple' */
+    dcur = third - second;
+    if (convexCompare(dcur)) {
+        if (!convexCheckTriple(dcur, dprev, &curDir, &dirChanges, &angleSign)) 
+            return false;
+        second = third;     /* Remember ptr to current point. */
+        dprev = dcur;       /* Remember current delta. */
+    }
+
+    /* and check for direction changes back to second vertex */
+    dcur = saveSecond - second;
+    if (!convexCheckTriple(dcur, dprev, &curDir, &dirChanges, &angleSign)) 
+        return false;
+
+    /* Decide on polygon type given accumulated status */
+    if (dirChanges > 2)
+        return false;
+
+    if (angleSign > 0 || angleSign < 0)
+        return true;
+    return false;
+}
+
 } // namespace LoopBlinnMathUtils
 } // namespace WebCore
 
diff --git a/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.h b/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.h
index b9d19c5..361d901 100644
--- a/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.h
+++ b/Source/WebCore/platform/graphics/gpu/LoopBlinnMathUtils.h
@@ -101,6 +101,9 @@ bool xRayCrossesLine(const XRay& xRay,
                      const FloatPoint lineEndpoints[2],
                      bool& ambiguous);
 
+
+bool isConvex(const FloatPoint* vertices, int nVertices);
+
 } // namespace LoopBlinnMathUtils
 
 } // namespace WebCore
diff --git a/Source/WebCore/platform/graphics/gpu/Shader.cpp b/Source/WebCore/platform/graphics/gpu/Shader.cpp
index 1b9bfd5..13c5ebf 100644
--- a/Source/WebCore/platform/graphics/gpu/Shader.cpp
+++ b/Source/WebCore/platform/graphics/gpu/Shader.cpp
@@ -140,7 +140,7 @@ String Shader::generateVertex(Shader::VertexType vertexType, Shader::FillType fi
     case TwoDimensional:
         builder.append(
             "uniform mat3 matrix;\n"
-            "attribute vec3 position;\n");
+            "attribute vec2 position;\n");
         break;
     case LoopBlinnInterior:
         builder.append(
@@ -167,7 +167,7 @@ String Shader::generateVertex(Shader::VertexType vertexType, Shader::FillType fi
 
     if (vertexType == TwoDimensional) {
         builder.append(
-            "gl_Position = vec4(matrix * position, 1.0);\n");
+            "gl_Position = vec4(matrix * vec3(position, 1.0), 1.0);\n");
     } else {
         builder.append(
             "gl_Position = worldViewProjection * vec4(position, 0.0, 1.0);\n");
@@ -179,7 +179,7 @@ String Shader::generateVertex(Shader::VertexType vertexType, Shader::FillType fi
 
     if (fillType == TextureFill) {
         builder.append(
-            "texCoord = texMatrix * position;\n");
+            "texCoord = texMatrix * vec3(position, 1.0);\n");
     }
 
     builder.append(
diff --git a/Source/WebCore/platform/graphics/gpu/SharedGraphicsContext3D.cpp b/Source/WebCore/platform/graphics/gpu/SharedGraphicsContext3D.cpp
index 662d6a8..b7b94c4 100644
--- a/Source/WebCore/platform/graphics/gpu/SharedGraphicsContext3D.cpp
+++ b/Source/WebCore/platform/graphics/gpu/SharedGraphicsContext3D.cpp
@@ -346,10 +346,10 @@ void SharedGraphicsContext3D::enableStencil(bool enable)
 void SharedGraphicsContext3D::useQuadVertices()
 {
     if (!m_quadVertices) {
-        float vertices[] = { 0.0f, 0.0f, 1.0f,
-                             1.0f, 0.0f, 1.0f,
-                             0.0f, 1.0f, 1.0f,
-                             1.0f, 1.0f, 1.0f };
+        float vertices[] = { 0.0f, 0.0f,
+                             1.0f, 0.0f,
+                             0.0f, 1.0f,
+                             1.0f, 1.0f };
         m_quadVertices = m_context->createBuffer();
         m_context->bindBuffer(GraphicsContext3D::ARRAY_BUFFER, m_quadVertices);
         m_context->bufferData(GraphicsContext3D::ARRAY_BUFFER, sizeof(vertices), vertices, GraphicsContext3D::STATIC_DRAW);
diff --git a/Source/WebCore/platform/graphics/gpu/SolidFillShader.cpp b/Source/WebCore/platform/graphics/gpu/SolidFillShader.cpp
index 78381f0..0a6e084 100644
--- a/Source/WebCore/platform/graphics/gpu/SolidFillShader.cpp
+++ b/Source/WebCore/platform/graphics/gpu/SolidFillShader.cpp
@@ -69,7 +69,7 @@ void SolidFillShader::use(const AffineTransform& transform, const Color& color)
     affineTo3x3(transform, matrix);
     m_context->uniformMatrix3fv(m_matrixLocation, false /*transpose*/, matrix, 1 /*count*/);
 
-    m_context->vertexAttribPointer(m_positionLocation, 3, GraphicsContext3D::FLOAT, false, 0, 0);
+    m_context->vertexAttribPointer(m_positionLocation, 2, GraphicsContext3D::FLOAT, false, 0, 0);
 
     m_context->enableVertexAttribArray(m_positionLocation);
 }
diff --git a/Source/WebCore/platform/graphics/gpu/TexShader.cpp b/Source/WebCore/platform/graphics/gpu/TexShader.cpp
index 9eb5c16..ac141a5 100644
--- a/Source/WebCore/platform/graphics/gpu/TexShader.cpp
+++ b/Source/WebCore/platform/graphics/gpu/TexShader.cpp
@@ -72,7 +72,7 @@ void TexShader::use(const AffineTransform& transform, const AffineTransform& tex
     m_context->uniform1i(m_samplerLocation, sampler);
     m_context->uniform1f(m_alphaLocation, alpha);
 
-    m_context->vertexAttribPointer(m_positionLocation, 3, GraphicsContext3D::FLOAT, false, 0, 0);
+    m_context->vertexAttribPointer(m_positionLocation, 2, GraphicsContext3D::FLOAT, false, 0, 0);
 
     m_context->enableVertexAttribArray(m_positionLocation);
 
diff --git a/Source/WebCore/platform/graphics/gpu/TilingData.cpp b/Source/WebCore/platform/graphics/gpu/TilingData.cpp
index 1370543..2415ee4 100644
--- a/Source/WebCore/platform/graphics/gpu/TilingData.cpp
+++ b/Source/WebCore/platform/graphics/gpu/TilingData.cpp
@@ -44,6 +44,9 @@ namespace WebCore {
 
 static int computeNumTiles(int maxTextureSize, int totalSize, int borderTexels)
 {
+    if (maxTextureSize - 2 * borderTexels <= 0)
+        return totalSize > 0 && maxTextureSize >= totalSize ? 1 : 0;
+
     int numTiles = max(1, 1 + (totalSize - 1 - 2 * borderTexels) / (maxTextureSize - 2 * borderTexels));
     return totalSize > 0 ? numTiles : 0;
 }