Prevent the usage of the texture(tile) if considered un-usable

As an example of gmail, even though clearView is called, the previous
content still show up.
This fix just use a usable flag to make sure the content
in the previously used texture is not showing up.

bug : 3215000

Change-Id: I5429a4d03547d4cd4ad10bd2153c247a4d40db7d

5 files changed, 38 insertions, 6 deletions

diff --git a/WebCore/platform/graphics/android/BaseTile.cpp b/WebCore/platform/graphics/android/BaseTile.cpp
index 0f4ab4f..5701486 100644
--- a/WebCore/platform/graphics/android/BaseTile.cpp
+++ b/WebCore/platform/graphics/android/BaseTile.cpp
@@ -73,6 +73,7 @@ BaseTile::BaseTile()
     , m_texture(0)
     , m_scale(1)
     , m_dirty(true)
+    , m_usable(true)
     , m_lastDirtyPicture(0)
     , m_lastPaintedPicture(0)
 {
@@ -84,7 +85,7 @@ BaseTile::BaseTile()
 BaseTile::~BaseTile()
 {
     setUsedLevel(-1);
-    if(m_texture)
+    if (m_texture)
         m_texture->release(this);
 
 #ifdef DEBUG_COUNT
@@ -138,6 +139,13 @@ void BaseTile::markAsDirty(int unsigned pictureCount)
         m_dirty = true;
 }
 
+void BaseTile::setUsable(bool usable)
+{
+    android::AutoMutex lock(m_atomicSync);
+    m_usable = usable;
+}
+
+
 bool BaseTile::isDirty()
 {
     android::AutoMutex lock(m_atomicSync);
@@ -159,6 +167,12 @@ void BaseTile::draw(float transparency, SkRect& rect)
         return;
     }
 
+    // Early return if set to un-usable in purpose!
+    if (!m_usable) {
+        XLOG("early return at BaseTile::draw b/c tile set to unusable !");
+        return;
+    }
+
     TextureInfo* textureInfo = m_texture->consumerLock();
     if (!textureInfo) {
         XLOG("%x (%d, %d) trying to draw, but no textureInfo!", this, x(), y());
@@ -201,7 +215,7 @@ void BaseTile::paintBitmap()
     float scale = m_scale;
     m_atomicSync.unlock();
 
-    if(!dirty || !texture)
+    if (!dirty || !texture)
         return;
 
     const int x = m_x;
@@ -251,8 +265,10 @@ void BaseTile::paintBitmap()
 
     m_atomicSync.lock();
     m_lastPaintedPicture = pictureCount;
-    if (m_lastPaintedPicture >= m_lastDirtyPicture)
+    if (m_lastPaintedPicture >= m_lastDirtyPicture) {
         m_dirty = false;
+        m_usable = true;
+    }
     m_atomicSync.unlock();
 }
 
diff --git a/WebCore/platform/graphics/android/BaseTile.h b/WebCore/platform/graphics/android/BaseTile.h
index 8f095e3..22e85d1 100644
--- a/WebCore/platform/graphics/android/BaseTile.h
+++ b/WebCore/platform/graphics/android/BaseTile.h
@@ -81,7 +81,7 @@ public:
 
     void markAsDirty(const unsigned int pictureCount);
     bool isDirty();
-
+    void setUsable(bool usable);
     float scale() const { return m_scale; }
     void setScale(float scale);
 
@@ -101,6 +101,8 @@ private:
     float m_scale;
     // used to signal that the that the tile is out-of-date and needs to be redrawn
     bool m_dirty;
+    // used to signal whether or not the draw can use this tile.
+    bool m_usable;
     // stores the id of the latest picture from webkit that caused this tile to
     // become dirty. A tile is no longer dirty when it has been painted with a
     // picture that is newer than this value.
diff --git a/WebCore/platform/graphics/android/GLWebViewState.cpp b/WebCore/platform/graphics/android/GLWebViewState.cpp
index 9bca91a..7c2f851 100644
--- a/WebCore/platform/graphics/android/GLWebViewState.cpp
+++ b/WebCore/platform/graphics/android/GLWebViewState.cpp
@@ -97,6 +97,10 @@ GLWebViewState::~GLWebViewState()
 void GLWebViewState::setBaseLayer(BaseLayerAndroid* layer, const IntRect& rect)
 {
     android::Mutex::Autolock lock(m_baseLayerLock);
+    if (!layer) {
+        m_tiledPageA->setUsable(false);
+        m_tiledPageB->setUsable(false);
+    }
     if (m_baseLayer && layer)
         m_baseLayer->swapExtra(layer);
     m_baseLayer = layer;
@@ -233,7 +237,8 @@ void GLWebViewState::setViewport(SkRect& viewport, float scale)
             static_cast<int>(ceilf(viewport.fBottom * invTileContentHeight)));
 }
 
-bool GLWebViewState::hasContent() {
+bool GLWebViewState::hasContent()
+{
     android::Mutex::Autolock lock(m_baseLayerLock);
     return m_baseLayer;
 }
diff --git a/WebCore/platform/graphics/android/TiledPage.cpp b/WebCore/platform/graphics/android/TiledPage.cpp
index 3a08f9b..1d2754d 100644
--- a/WebCore/platform/graphics/android/TiledPage.cpp
+++ b/WebCore/platform/graphics/android/TiledPage.cpp
@@ -105,6 +105,15 @@ BaseTile* TiledPage::getBaseTile(int x, int y) const
     return 0;
 }
 
+void TiledPage::setUsable(bool usable)
+{
+    for (int j = 0; j < m_baseTileSize; j++) {
+        BaseTile& tile = m_baseTiles[j];
+        tile.setUsable(usable);
+    }
+    return;
+}
+
 void TiledPage::invalidateRect(const IntRect& inval, const unsigned int pictureCount)
 {
     // Given the current scale level we need to mark the appropriate tiles as dirty
diff --git a/WebCore/platform/graphics/android/TiledPage.h b/WebCore/platform/graphics/android/TiledPage.h
index fa310bf..ad88bc4 100644
--- a/WebCore/platform/graphics/android/TiledPage.h
+++ b/WebCore/platform/graphics/android/TiledPage.h
@@ -75,7 +75,7 @@ public:
     void setScale(float scale) { m_scale = scale; m_invScale = 1 / scale; }
 
     void invalidateRect(const IntRect& invalRect, const unsigned int pictureCount);
-
+    void setUsable(bool usable);
 private:
     void updateTileState(const SkIRect& tileBounds);
     void prepareRow(bool goingLeft, int tilesInRow, int firstTileX, int y, TileSet* set);