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"
 #include "base/metrics/histogram.h"
 #include "base/numerics/safe_math.h"
 #include "base/stl_util.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/trace_event/trace_event.h"
-#include "cc/base/math_util.h"
 #include "cc/resources/platform_color.h"
+#include "cc/resources/resource_util.h"
 #include "cc/resources/returned_resource.h"
 #include "cc/resources/shared_bitmap_manager.h"
 #include "cc/resources/transferable_resource.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "gpu/command_buffer/client/gpu_memory_buffer_manager.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "third_party/khronos/GLES2/gl2ext.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "third_party/skia/include/gpu/GrContext.h"
@@ skipping 682 matching lines @@
     dest.writePixels(source_info, image, image_stride, 0, 0);
   } else {
     DCHECK(resource->gl_id);
     DCHECK(!resource->pending_set_pixels);
     DCHECK_EQ(resource->target, static_cast<GLenum>(GL_TEXTURE_2D));
     GLES2Interface* gl = ContextGL();
     DCHECK(gl);
     gl->BindTexture(GL_TEXTURE_2D, resource->gl_id);
 
     if (resource->format == ETC1) {
-      base::CheckedNumeric<int> num_bytes = BitsPerPixel(ETC1);
-      num_bytes *= image_size.width();
-      num_bytes *= image_size.height();
-      num_bytes /= 8;
+      int image_bytes = ResourceUtil::CheckedSizeInBytes(image_size, ETC1);

[vmpstr, 2015/07/16 19:04:00]

This will cause a possible truncation size_t -> int. I think you need to keep an
explicit CheckedNumeric here, since CompressedTexImage2D takes an int.

       gl->CompressedTexImage2D(GL_TEXTURE_2D, 0, GLInternalFormat(ETC1),
                                image_size.width(), image_size.height(), 0,
-                               num_bytes.ValueOrDie(), image);
+                               image_bytes, image);
     } else {
       gl->TexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, image_size.width(),
                         image_size.height(), GLDataFormat(resource->format),
                         GLDataType(resource->format), image);
     }
   }
 }
 
 ResourceProvider::Resource* ResourceProvider::InsertResource(
     ResourceId id,
@@ skipping 779 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);
+  int resource_bytes = ResourceUtil::UncheckedSizeInBytesAligned(

[vmpstr, 2015/07/16 19:04:00]

I don't think this will compile on windows because of a truncation warning.

[prashant.n, 2015/07/22 15:44:58]

I'll change this to size_t. But BufferData takes singed long int for second
parameter, which again can lead to truncation when actually passed to function.
But currently resource size is upto (512*512*4), so we may not get the
truncation problem.

+      resource->size, resource->format);
+  gl->BufferData(GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM, resource_bytes, 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