Fix a rendering bug when frames have no dirty rect on display list mode.

Source/platform/graphics/RecordingImageBufferSurface.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "platform/graphics/RecordingImageBufferSurface.h"
 
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/ImageBuffer.h"
@@ skipping 10 matching lines @@
     , m_imageBuffer(0)
     , m_initialSaveCount(0)
     , m_frameWasCleared(true)
 {
     initializeCurrentFrame();
 }
 
 RecordingImageBufferSurface::~RecordingImageBufferSurface()
 { }
 
-void RecordingImageBufferSurface::initializeCurrentFrame()
+bool RecordingImageBufferSurface::initializeCurrentFrame()
 {
+    StateStack stateStack;
+    bool saved = false;
+    if (m_currentFrame) {
+        saved = saveState(m_currentFrame->getRecordingCanvas(), &stateStack);
+        if (!saved)
+            return false;
+    }
+
     static SkRTreeFactory rTreeFactory;
     m_currentFrame = adoptPtr(new SkPictureRecorder);
     m_currentFrame->beginRecording(size().width(), size().height(), &rTreeFactory);
     m_initialSaveCount = m_currentFrame->getRecordingCanvas()->getSaveCount();
     if (m_imageBuffer) {
         m_imageBuffer->context()->resetCanvas(m_currentFrame->getRecordingCanvas());
         m_imageBuffer->context()->setRegionTrackingMode(GraphicsContext::RegionTrackingOverwrite);
     }
+
+    if (saved)
+        setCurrentState(m_currentFrame->getRecordingCanvas(), &stateStack);
+
+    return true;
 }
 
 void RecordingImageBufferSurface::setImageBuffer(ImageBuffer* imageBuffer)
 {
     m_imageBuffer = imageBuffer;
     if (m_currentFrame && m_imageBuffer) {
         m_imageBuffer->context()->setRegionTrackingMode(GraphicsContext::RegionTrackingOverwrite);
         m_imageBuffer->context()->resetCanvas(m_currentFrame->getRecordingCanvas());
     }
 }
@@ skipping 76 matching lines @@
 
     if (!m_currentFrame) {
         return false;
     }
 
     IntRect canvasRect(IntPoint(0, 0), size());
     if (!m_frameWasCleared && !m_imageBuffer->context()->opaqueRegion().asRect().contains(canvasRect)) {
         return false;
     }
 
-    StateStack stateStack;
-
-    if (!saveState(m_currentFrame->getRecordingCanvas(), &stateStack)) {
-        return false;
-    }
-
     m_previousFrame = adoptRef(m_currentFrame->endRecording());
-    initializeCurrentFrame();
+    if (!initializeCurrentFrame())
+        return false;
 
-    setCurrentState(m_currentFrame->getRecordingCanvas(), &stateStack);
 
     m_frameWasCleared = false;
     return true;
 }
 
 bool RecordingImageBufferSurface::saveState(SkCanvas* srcCanvas, StateStack* stateStack)
 {
     StateRec state;
 
     // we will remove all the saved state stack in endRecording anyway, so it makes no difference
@@ skipping 24 matching lines @@
         dstCanvas->save();
         stateStack->pop();
     }
 
     dstCanvas->resetMatrix();
     dstCanvas->clipRect(SkRect::MakeFromIRect(stateStack->peek().m_clip));
     dstCanvas->setMatrix(stateStack->peek().m_ctm);
 }
 
 } // namespace blink