Performance improvements in GraphicsLayer: implement the simple image code path.

Bug:2599955
Change-Id: I530a02c64abff40223005d6dc07c7495ca475ffe

3 files changed, 37 insertions, 7 deletions

diff --git a/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp b/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
index b8a3610..201022a 100644
--- a/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
+++ b/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
@@ -451,7 +451,7 @@ bool GraphicsLayerAndroid::repaint(const FloatRect& rect)
         this, rect.x(), rect.y(), rect.width(), rect.height(),
         gPaused, m_needsRepaint, m_haveContents);
 
-    if (!gPaused && m_haveContents && m_needsRepaint) {
+    if (!gPaused && m_haveContents && m_needsRepaint && !m_haveImage) {
         SkAutoPictureRecord arp(m_contentLayer->recordContext(), m_size.width(), m_size.height());
         SkCanvas* recordingCanvas = arp.getRecordingCanvas();
 
@@ -814,11 +814,10 @@ void GraphicsLayerAndroid::setContentsToImage(Image* image)
     TLOG("(%x) setContentsToImage", this, image);
     if (image) {
         m_haveContents = true;
-        if (!m_haveImage) {
-            m_haveImage = true;
-            setNeedsDisplay();
-            askForSync();
-        }
+        m_haveImage = true;
+        m_contentLayer->setContentsImage(image->nativeImageForCurrentFrame());
+        setNeedsDisplay();
+        askForSync();
     }
 }
 
diff --git a/WebCore/platform/graphics/android/LayerAndroid.cpp b/WebCore/platform/graphics/android/LayerAndroid.cpp
index d6ba0a1..7c3f5d4 100644
--- a/WebCore/platform/graphics/android/LayerAndroid.cpp
+++ b/WebCore/platform/graphics/android/LayerAndroid.cpp
@@ -5,6 +5,7 @@
 
 #include "AndroidAnimation.h"
 #include "DrawExtra.h"
+#include "SkBitmapRef.h"
 #include "SkCanvas.h"
 #include "SkDrawFilter.h"
 #include "SkPaint.h"
@@ -50,6 +51,7 @@ LayerAndroid::LayerAndroid(bool isRootLayer) : SkLayer(),
     m_doRotation(false),
     m_isFixed(false),
     m_recordingPicture(0),
+    m_contentsImage(0),
     m_extra(0),
     m_uniqueId(++gUniqueId)
 {
@@ -69,6 +71,8 @@ LayerAndroid::LayerAndroid(const LayerAndroid& layer) : SkLayer(layer),
 {
     m_doRotation = layer.m_doRotation;
     m_isFixed = layer.m_isFixed;
+    m_contentsImage = layer.m_contentsImage;
+    m_contentsImage->safeRef();
 
     m_angleTransform = layer.m_angleTransform;
     m_translation = layer.m_translation;
@@ -106,6 +110,7 @@ LayerAndroid::LayerAndroid(SkPicture* picture) : SkLayer(),
     m_doRotation(false),
     m_isFixed(false),
     m_recordingPicture(picture),
+    m_contentsImage(0),
     m_extra(0),
     m_uniqueId(-1)
 {
@@ -120,6 +125,7 @@ LayerAndroid::LayerAndroid(SkPicture* picture) : SkLayer(),
 LayerAndroid::~LayerAndroid()
 {
     removeChildren();
+    m_contentsImage->safeUnref();
     m_recordingPicture->safeUnref();
     m_animations.clear();
     gDebugLayerAndroidInstances--;
@@ -318,6 +324,10 @@ void LayerAndroid::updatePositions() {
     }
 }
 
+void LayerAndroid::setContentsImage(SkBitmapRef* img) {
+    SkRefCnt_SafeAssign(m_contentsImage, img);
+}
+
 void LayerAndroid::onDraw(SkCanvas* canvas, SkScalar opacity) {
     if (m_haveClip) {
         SkRect r;
@@ -335,7 +345,13 @@ void LayerAndroid::onDraw(SkCanvas* canvas, SkScalar opacity) {
     if (canvasOpacity < 255)
         canvas->setDrawFilter(new OpacityDrawFilter(canvasOpacity));
 
-    canvas->drawPicture(*m_recordingPicture);
+    if (m_contentsImage) {
+      SkRect dest;
+      dest.set(0, 0, getSize().width(), getSize().height());
+      canvas->drawBitmapRect(m_contentsImage->bitmap(), 0, dest);
+    } else {
+      canvas->drawPicture(*m_recordingPicture);
+    }
     if (m_extra)
         m_extra->draw(canvas, this);
 
diff --git a/WebCore/platform/graphics/android/LayerAndroid.h b/WebCore/platform/graphics/android/LayerAndroid.h
index ef6af3b..2b106d1 100644
--- a/WebCore/platform/graphics/android/LayerAndroid.h
+++ b/WebCore/platform/graphics/android/LayerAndroid.h
@@ -32,6 +32,7 @@
 #define bzero(b,len) (memset((b), '\0', (len)), (void) 0)
 #endif
 
+class SkBitmapRef;
 class SkCanvas;
 class SkMatrix;
 class SkPicture;
@@ -174,6 +175,13 @@ public:
     int getFixedWidth() { return m_fixedWidth; }
     int getFixedHeight() { return m_fixedHeight; }
 
+    /** This sets a content image -- calling it means we will use
+        the image directly when drawing the layer instead of using
+        the content painted by WebKit. See comments below for
+        m_recordingPicture and m_contentsImage.
+    */
+    void setContentsImage(SkBitmapRef* img);
+
 protected:
     virtual void onDraw(SkCanvas*, SkScalar opacity);
 
@@ -209,7 +217,14 @@ private:
     SkScalar m_angleTransform;
     SkColor m_backgroundColor;
 
+    // Note that m_recordingPicture and m_contentsImage are mutually exclusive;
+    // m_recordingPicture is used when WebKit is asked to paint the layer's
+    // content, while m_contentsImage contains an image that we directly
+    // composite, using the layer's dimensions as a destination rect.
+    // We do this as if the layer only contains an image, directly compositing
+    // it is a much faster method than using m_recordingPicture.
     SkPicture* m_recordingPicture;
+    SkBitmapRef* m_contentsImage;
 
     typedef HashMap<String, RefPtr<AndroidAnimation> > KeyframesMap;
     KeyframesMap m_animations;