Revert of Fix ASSERT(m_canvas) failures when contextDisabled()

Revert of Fix ASSERT(m_canvas) failures when contextDisabled() (patchset #3 id:40001 of https://codereview.chromium.org/987383003/)

Reason for revert:
It seems that the presumption that contextDisabled is just a SP counterpart of non-SP's SkNullCanvas is wrong.

Original issue's description:
> Fix ASSERT(m_canvas) failures when contextDisabled()
> 
> contextDisabled() is for performance tests to let GraphicsContext to
> draw nothing. In either slimming-paint mode or non-slimming-paint mode,
> we should check it at beginning of every drawing method of
> GraphicsContext to ensure the performance when contextDisabled() is
> as expected.
> 
> Especially in slimming-paint mode, missing the check causes null
> dereference of m_canvas or ASSERT(m_canvas) failure.
> 
> - Ensure contextDisabled() is checked in all drawing methods of
>   GraphicsContext;
> - Use SkNullCanvas when contextDisabled() to ensure drawings directly
>   using GraphicsContext::canvas() will not encounter null canvas and
>   be also controled by contextDisabled().
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=191673

TBR=chrishtr@chromium.org,fmalita@chromium.org,pdr@chromium.org,schenney@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=191716

[Xianzhu, 2015-03-11 16:19:26]

Created Revert of Fix ASSERT(m_canvas) failures when contextDisabled()

[commit-bot: I haz the power, 2015-03-11 16:19:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/997113004/1

[commit-bot: I haz the power, 2015-03-11 16:20:21]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-03-11 16:20:22]

Failed to apply patch for Source/platform/graphics/GraphicsContext.cpp:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file Source/platform/graphics/GraphicsContext.cpp
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  1 out of 61 hunks FAILED -- saving rejects to file
Source/platform/graphics/GraphicsContext.cpp.rej

Patch:       Source/platform/graphics/GraphicsContext.cpp
Index: Source/platform/graphics/GraphicsContext.cpp
diff --git a/Source/platform/graphics/GraphicsContext.cpp
b/Source/platform/graphics/GraphicsContext.cpp
index
62d3bfe74b460331db7e7d255947ea065e131c65..de87ce856ffeed8e9169984eb310490db4742c85
100644
--- a/Source/platform/graphics/GraphicsContext.cpp
+++ b/Source/platform/graphics/GraphicsContext.cpp
@@ -53,7 +53,6 @@
 #include "third_party/skia/include/effects/SkPictureImageFilter.h"
 #include "third_party/skia/include/gpu/GrRenderTarget.h"
 #include "third_party/skia/include/gpu/GrTexture.h"
-#include "third_party/skia/include/utils/SkNullCanvas.h"
 #include "wtf/Assertions.h"
 #include "wtf/MathExtras.h"
 
@@ -82,12 +81,6 @@
     SkCanvas* m_savedCanvas;
     const SkMatrix m_savedMatrix;
 };
-
-static SkCanvas* nullCanvas()
-{
-    DEFINE_STATIC_LOCAL(RefPtr<SkCanvas>, nullCanvas,
(adoptRef(SkCreateNullCanvas())));
-    return nullCanvas.get();
-}
 
 GraphicsContext::GraphicsContext(SkCanvas* canvas, DisplayItemList*
displayItemList, DisabledMode disableContextOrPainting)
     : m_canvas(canvas)
@@ -137,6 +130,9 @@
 
 void GraphicsContext::save()
 {
+    if (contextDisabled())
+        return;
+
     m_paintState->incrementSaveCount();
 
     ASSERT(m_canvas);
@@ -145,6 +141,9 @@
 
 void GraphicsContext::restore()
 {
+    if (contextDisabled())
+        return;
+
     if (!m_paintStateIndex && !m_paintState->saveCount()) {
         WTF_LOG_ERROR("ERROR void GraphicsContext::restore() stack is empty");
         return;
@@ -177,18 +176,29 @@
 
 void GraphicsContext::saveLayer(const SkRect* bounds, const SkPaint* paint)
 {
-    ASSERT(m_canvas);
+    if (contextDisabled())
+        return;
+
+    ASSERT(m_canvas);
+
     m_canvas->saveLayer(bounds, paint);
 }
 
 void GraphicsContext::restoreLayer()
 {
-    ASSERT(m_canvas);
+    if (contextDisabled())
+        return;
+
+    ASSERT(m_canvas);
+
     m_canvas->restore();
 }
 
 void GraphicsContext::beginAnnotation(const AnnotationList& annotations)
 {
+    if (contextDisabled())
+        return;
+
     ASSERT(m_canvas);
 
     canvas()->beginCommentGroup("GraphicsContextAnnotation");
@@ -204,6 +214,9 @@
 
 void GraphicsContext::endAnnotation()
 {
+    if (contextDisabled())
+        return;
+
     ASSERT(m_canvas);
     ASSERT(m_annotationCount > 0);
     canvas()->endCommentGroup();
@@ -224,6 +237,9 @@
 
 void GraphicsContext::setStrokePattern(PassRefPtr<Pattern> pattern, float
alpha)
 {
+    if (contextDisabled())
+        return;
+
     ASSERT(pattern);
     if (!pattern) {
         setStrokeColor(Color::black);
@@ -235,6 +251,9 @@
 
 void GraphicsContext::setStrokeGradient(PassRefPtr<Gradient> gradient, float
alpha)
 {
+    if (contextDisabled())
+        return;
+
     ASSERT(gradient);
     if (!gradient) {
         setStrokeColor(Color::black);
@@ -245,6 +264,9 @@
 
 void GraphicsContext::setFillPattern(PassRefPtr<Pattern> pattern, float alpha)
 {
+    if (contextDisabled())
+        return;
+
     ASSERT(pattern);
     if (!pattern) {
         setFillColor(Color::black);
@@ -256,6 +278,9 @@
 
 void GraphicsContext::setFillGradient(PassRefPtr<Gradient> gradient, float
alpha)
 {
+    if (contextDisabled())
+        return;
+
     ASSERT(gradient);
     if (!gradient) {
         setFillColor(Color::black);
@@ -269,6 +294,9 @@
     DrawLooperBuilder::ShadowTransformMode shadowTransformMode,
     DrawLooperBuilder::ShadowAlphaMode shadowAlphaMode, ShadowMode shadowMode)
 {
+    if (contextDisabled())
+        return;
+
     OwnPtr<DrawLooperBuilder> drawLooperBuilder = DrawLooperBuilder::create();
     if (!color.alpha()) {
         if (shadowMode == DrawShadowOnly) {
@@ -301,21 +329,33 @@
 
 void GraphicsContext::setDrawLooper(PassOwnPtr<DrawLooperBuilder>
drawLooperBuilder)
 {
+    if (contextDisabled())
+        return;
+
     mutableState()->setDrawLooper(drawLooperBuilder->detachDrawLooper());
 }
 
 void GraphicsContext::clearDrawLooper()
 {
+    if (contextDisabled())
+        return;
+
     mutableState()->clearDrawLooper();
 }
 
 void GraphicsContext::setDropShadowImageFilter(PassRefPtr<SkImageFilter>
imageFilter)
 {
+    if (contextDisabled())
+        return;
+
     mutableState()->setDropShadowImageFilter(imageFilter);
 }
 
 void GraphicsContext::clearDropShadowImageFilter()
 {
+    if (contextDisabled())
+        return;
+
     mutableState()->clearDropShadowImageFilter();
 }
 
@@ -326,6 +366,8 @@
 
 bool GraphicsContext::getTransformedClipBounds(FloatRect* bounds) const
 {
+    if (contextDisabled())
+        return false;
     ASSERT(m_canvas);
     SkIRect skIBounds;
     if (!m_canvas->getClipDeviceBounds(&skIBounds))
@@ -342,7 +384,7 @@
     if (RuntimeEnabledFeatures::slimmingPaintEnabled())
         return SkMatrix::I();
 
-    if (!m_canvas)
+    if (contextDisabled() || !m_canvas)
         return SkMatrix::I();
 
     ASSERT(m_canvas);
@@ -358,6 +400,9 @@
 
 void GraphicsContext::adjustTextRenderMode(SkPaint* paint) const
 {
+    if (contextDisabled())
+        return;
+
     if (!paint->isLCDRenderText())
         return;
 
@@ -373,6 +418,8 @@
 
 void GraphicsContext::setCompositeOperation(SkXfermode::Mode xferMode)
 {
+    if (contextDisabled())
+        return;
     mutableState()->setCompositeOperation(xferMode);
 }
 
@@ -403,18 +450,28 @@
 
 bool GraphicsContext::readPixels(const SkImageInfo& info, void* pixels, size_t
rowBytes, int x, int y)
 {
+    if (contextDisabled())
+        return false;
+
     ASSERT(m_canvas);
     return m_canvas->readPixels(info, pixels, rowBytes, x, y);
 }
 
 void GraphicsContext::setMatrix(const SkMatrix& matrix)
 {
-    ASSERT(m_canvas);
+    if (contextDisabled())
+        return;
+
+    ASSERT(m_canvas);
+
     m_canvas->setMatrix(matrix);
 }
 
 void GraphicsContext::concat(const SkMatrix& matrix)
 {
+    if (contextDisabled())
+        return;
+
     if (matrix.isIdentity())
         return;
 
@@ -430,6 +487,9 @@
 
 void GraphicsContext::beginLayer(float opacity, SkXfermode::Mode xfermode,
const FloatRect* bounds, ColorFilter colorFilter, SkImageFilter* imageFilter)
 {
+    if (contextDisabled())
+        return;
+
     SkPaint layerPaint;
     layerPaint.setAlpha(static_cast<unsigned char>(opacity * 255));
     layerPaint.setXfermodeMode(xfermode);
@@ -448,6 +508,9 @@
 
 void GraphicsContext::endLayer()
 {
+    if (contextDisabled())
+        return;
+
     restoreLayer();
 
     ASSERT(m_layerCount > 0);
@@ -456,24 +519,27 @@
 
 void GraphicsContext::beginRecording(const FloatRect& bounds, uint32_t
recordFlags)
 {
+    if (contextDisabled())
+        return;
+
     m_recordingStateStack.append(
         RecordingState::Create(m_canvas, getTotalMatrix()));
-    m_canvas = contextDisabled() ? nullCanvas() :
m_recordingStateStack.last()->recorder().beginRecording(bounds, 0, recordFlags);
+   …
(message too large)

[commit-bot: I haz the power, 2015-03-11 16:20:30]

The CQ bit was unchecked by commit-bot@chromium.org

[Xianzhu, 2015-03-11 16:52:51]

The CQ bit was checked by wangxianzhu@chromium.org

[commit-bot: I haz the power, 2015-03-11 16:53:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/997113004/40001

[commit-bot: I haz the power, 2015-03-11 16:53:39]

Committed patchset #2 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=191716