Fix a crash when saving a <canvas> or <img> image which is large.

content/renderer/render_view_browsertest.cc

Index: content/renderer/render_view_browsertest.cc
diff --git a/content/renderer/render_view_browsertest.cc b/content/renderer/render_view_browsertest.cc
index e3ed9fad6c0bc1f7512f02501f3f2ea6d6d962a9..55b6ff059e9ea1a1378f0b68fc5540829cd96355 100644
--- a/content/renderer/render_view_browsertest.cc
+++ b/content/renderer/render_view_browsertest.cc
@@ -292,6 +292,54 @@ class RenderViewImplTest : public RenderViewTest {
   scoped_ptr<MockKeyboard> mock_keyboard_;
 };
 
+TEST_F(RenderViewImplTest, SaveImageFromDataURL) {
+  const IPC::Message* msg1 = render_thread_->sink().GetFirstMessageMatching(
+      ViewHostMsg_SaveImageFromDataURL::ID);
+  EXPECT_FALSE(msg1);
+  render_thread_->sink().ClearMessages();
+
+  const std::string image_data_url =
+      "data:image/gif;base64,R0lGODlhAQABAIAAAAUEBAAAACwAAAAAAQABAAACAkQBADs=";
+
+  view()->saveImageFromDataURL(WebString::fromUTF8(image_data_url));
+  ProcessPendingMessages();
+  const IPC::Message* msg2 = render_thread_->sink().GetFirstMessageMatching(
+      ViewHostMsg_SaveImageFromDataURL::ID);
+  EXPECT_TRUE(msg2);
+
+  ViewHostMsg_SaveImageFromDataURL::Param param1;
+  ViewHostMsg_SaveImageFromDataURL::Read(msg2, &param1);
+  EXPECT_EQ(param1.b.length(), image_data_url.length());
+  EXPECT_EQ(param1.b, image_data_url);
+
+  ProcessPendingMessages();
+  render_thread_->sink().ClearMessages();
+
+  const std::string large_data_url(1024 * 1024 * 10 - 1, 'd');
+
+  view()->saveImageFromDataURL(WebString::fromUTF8(large_data_url));
+  ProcessPendingMessages();
+  const IPC::Message* msg3 = render_thread_->sink().GetFirstMessageMatching(
+      ViewHostMsg_SaveImageFromDataURL::ID);
+  EXPECT_TRUE(msg3);
+
+  ViewHostMsg_SaveImageFromDataURL::Param param2;
+  ViewHostMsg_SaveImageFromDataURL::Read(msg3, &param2);
+  EXPECT_EQ(param2.b.length(), large_data_url.length());
+  EXPECT_EQ(param2.b, large_data_url);
+
+  ProcessPendingMessages();
+  render_thread_->sink().ClearMessages();
+
+  const std::string exceeded_data_url(1024 * 1024 * 10 + 1, 'd');
+
+  view()->saveImageFromDataURL(WebString::fromUTF8(exceeded_data_url));
+  ProcessPendingMessages();
+  const IPC::Message* msg4 = render_thread_->sink().GetFirstMessageMatching(
+      ViewHostMsg_SaveImageFromDataURL::ID);
+  EXPECT_FALSE(msg4);
+}
+
 // Test that we get form state change notifications when input fields change.
 TEST_F(RenderViewImplTest, DISABLED_OnNavStateChanged) {
   // Don't want any delay for form state sync changes. This will still post a