cc: Fix BytesPerPixel issue and refactor.

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index f081f6236f87a36410537af4a9c0e570f1191510..b7a935db7040e182bc9590d314dd98b5b8c7616d 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -14,8 +14,8 @@
 #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"
@@ -718,13 +718,10 @@ void ResourceProvider::CopyToResource(ResourceId id,
     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),
@@ -1524,12 +1521,10 @@ void ResourceProvider::AcquirePixelBuffer(ResourceId 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);
 }