Fix crash in GotAcceleratedIOSurfaceFrame

content/browser/renderer_host/compositing_iosurface_layer_mac.mm

 // Copyright 2013 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 "content/browser/renderer_host/compositing_iosurface_layer_mac.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <OpenGL/gl.h>
 
 #include "base/mac/mac_util.h"
@@ skipping 84 matching lines @@
 
 void CompositingIOSurfaceLayerHelper::DidDraw(bool success) {
   needs_display_ = false;
   AckPendingFrame(success);
 }
 
 void CompositingIOSurfaceLayerHelper::AckPendingFrame(bool success) {
   if (!has_pending_frame_)
     return;
   has_pending_frame_ = false;
-  client_->AcceleratedLayerDidDrawFrame(success);
+  if (success)
+    client_->AcceleratedLayerDidDrawFrame();
+  else
+    client_->AcceleratedLayerHitError();
   // A trace value of 0 indicates that there is no longer a pending swap ack.
   TRACE_COUNTER_ID1("browser", "PendingSwapAck", this, 0);
 }
 
 void CompositingIOSurfaceLayerHelper::SetNeedsDisplayAndDisplayAndAck() {
   // Drawing using setNeedsDisplay and displayIfNeeded will result in
   // subsequent canDrawInCGLContext callbacks getting dropped, and jerky
   // animation. Disable asynchronous drawing before issuing these calls as a
   // workaround.
   // http://crbug.com/395827
@@ skipping 51 matching lines @@
 }
 
 - (content::CompositingIOSurfaceContext*)context {
   return context_.get();
 }
 
 - (id)initWithIOSurface:(scoped_refptr<content::CompositingIOSurfaceMac>)
                             iosurface
         withScaleFactor:(float)scale_factor
              withClient:(content::CompositingIOSurfaceLayerClient*)client {
+  DCHECK(iosurface);
   if (self = [super init]) {
     helper_.reset(new content::CompositingIOSurfaceLayerHelper(client, self));
 
     iosurface_ = iosurface;
     context_ = content::CompositingIOSurfaceContext::Get(
         content::CompositingIOSurfaceContext::kCALayerContextWindowNumber);
-    DCHECK(context_);
+    if (!context_) {
+      LOG(ERROR) << "Failed create CompositingIOSurfaceContext";

[Ken Russell (switch to Gerrit), 2014/08/07 22:11:44]

I wonder whether here and throughout these classes VLOG should be used instead
of LOG to reduce the amount of output emitted by default, though I realize these
are only displayed in fairly serious error conditions.

[ccameron, 2014/08/07 22:28:24]

If anything, I'd like to make these errors more visible -- I'd like them to
appear in about:gpu, if possible -- is there a way to do that in the browser
process?

+      [self resetClient];
+      [self release];
+      return nil;
+    }
 
     [self setBackgroundColor:CGColorGetConstantColor(kCGColorWhite)];
     [self setAnchorPoint:CGPointMake(0, 0)];
     // Setting contents gravity is necessary to prevent the layer from being
     // scaled during dyanmic resizes (especially with devtools open).
     [self setContentsGravity:kCAGravityTopLeft];
     if ([self respondsToSelector:(@selector(setContentsScale:))]) {
       [self setContentsScale:scale_factor];
     }
   }
@@ skipping 88 matching lines @@
   if (helper_)
     helper_->DidDraw(draw_succeeded);
 
   [super drawInCGLContext:glContext
               pixelFormat:pixelFormat
              forLayerTime:timeInterval
               displayTime:timeStamp];
 }
 
 @end