cc: Fix BytesPerPixel issue and refactor.

cc/resources/resource_provider.cc

 // Copyright 2012 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 "cc/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/containers/hash_tables.h"
@@ skipping 1506 matching lines @@
   DCHECK(!resource->image_id);
   DCHECK_NE(ETC1, resource->format);
 
   DCHECK_EQ(RESOURCE_TYPE_GL_TEXTURE, resource->type);
   GLES2Interface* gl = ContextGL();
   DCHECK(gl);
   if (!resource->gl_pixel_buffer_id)
     resource->gl_pixel_buffer_id = buffer_id_allocator_->NextId();
   gl->BindBuffer(GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM,
                  resource->gl_pixel_buffer_id);
-  unsigned bytes_per_pixel = BitsPerPixel(resource->format) / 8;
-  gl->BufferData(
-      GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM,
-      resource->size.height() *
-          MathUtil::RoundUp(bytes_per_pixel * resource->size.width(), 4u),
-      NULL, GL_DYNAMIC_DRAW);
+
+  base::CheckedNumeric<int> num_bytes = resource->size.height();

[reveman, 2015/06/24 18:02:26]

why CheckedNumeric?

+  int bytes_per_row_aligned =

[reveman, 2015/06/24 18:02:26]

How about just bytes_per_row and round up to multiple of 4 in the call below as
before?

+      (resource->size.width() * BitsPerPixel(resource->format)) / 8;
+  bytes_per_row_aligned = MathUtil::RoundUp(bytes_per_row, 4u);
+  num_bytes *= bytes_per_row_aligned;
+
+  gl->BufferData(GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM,
+                 num_bytes.ValueOrDie(), NULL, GL_DYNAMIC_DRAW);
   gl->BindBuffer(GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM, 0);
 }
 
 void ResourceProvider::ReleasePixelBuffer(ResourceId id) {
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cc.debug"),
                "ResourceProvider::ReleasePixelBuffer");
 
   Resource* resource = GetResource(id);
   DCHECK(resource->origin == Resource::INTERNAL);
   DCHECK_EQ(resource->exported_count, 0);
@@ skipping 402 matching lines @@
 }
 
 class GrContext* ResourceProvider::GrContext(bool worker_context) const {
   ContextProvider* context_provider =
       worker_context ? output_surface_->worker_context_provider()
                      : output_surface_->context_provider();
   return context_provider ? context_provider->GrContext() : NULL;
 }
 
 }  // namespace cc