Fix crash when allocation of very large HTML canvas fails.

skia/ext/platform_canvas.cc

 // Copyright (c) 2011 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 "skia/ext/platform_canvas.h"
 
 #include "skia/ext/bitmap_platform_device.h"
 #include "third_party/skia/include/core/SkTypes.h"
 
 namespace skia {
@@ skipping 16 matching lines @@
 
   setDevice(device);
   device->unref();  // Was created with refcount 1, and setDevice also refs.
   return true;
 }
 
 SkCanvas* CreateBitmapCanvas(int width, int height, bool is_opaque) {
   return new PlatformCanvas(width, height, is_opaque);
 }
 
+SkCanvas* TryCreateBitmapCanvas(int width, int height, bool is_opaque) {

[alokp, 2011/08/19 15:34:39]

Couldn't you change the existing function to return NULL?

[junov1, 2011/08/19 15:50:25]

There are many places that currently call CreateBitmapCanvas and require it to
succeed (no graceful failure path).  The way in which CreateBitmapCanvas crashes
is actually very useful because it provides some diagnostics (see
CrashForBitmapAllocationFailure in platform_canvas_win.cc).

+  PlatformCanvas* canvas = new PlatformCanvas();
+  if (!canvas->initialize(width, height, is_opaque)) {
+    delete canvas;
+    canvas = NULL;
+  }
+  return canvas;
+}
+
 SkDevice* GetTopDevice(const SkCanvas& canvas) {
   SkCanvas::LayerIter iter(const_cast<SkCanvas*>(&canvas), false);
   return iter.device();
 }
 
 bool SupportsPlatformPaint(const SkCanvas* canvas) {
   // TODO(alokp): Rename IsNativeFontRenderingAllowed after removing these
   // calls from WebKit.
   PlatformDevice* platform_device = GetPlatformDevice(GetTopDevice(*canvas));
   return platform_device && platform_device->IsNativeFontRenderingAllowed();
@@ skipping 20 matching lines @@
     platform_device->DrawToNativeContext(context, x, y, src_rect);
 }
 
 void MakeOpaque(SkCanvas* canvas, int x, int y, int width, int height) {
   PlatformDevice* platform_device = GetPlatformDevice(GetTopDevice(*canvas));
   if (platform_device)
     platform_device->MakeOpaque(x, y, width, height);
 }
 
 }  // namespace skia