Update GPU memory buffers to use StrideInBytes internally.

Tile texture compression will add support for GPU memory buffer formats
that use less than a byte per pixel.

This CL prepares GPU buffers for this by using a new function
StrideInBytes instead of relying on bytes per pixel calculations when
calculating the number of bytes needed to store a certain number of pixels.

BUG=434699

Review URL: https://codereview.chromium.org/806653006

Cr-Commit-Position: refs/heads/master@{#311862}

1 files changed, 5 insertions, 4 deletions

diff --git a/gpu/command_buffer/tests/gl_manager.cc b/gpu/command_buffer/tests/gl_manager.cc
index 1075c42..8f4b330 100644
--- a/gpu/command_buffer/tests/gl_manager.cc
+++ b/gpu/command_buffer/tests/gl_manager.cc
@@ -38,11 +38,11 @@
 namespace gpu {
 namespace {
 
-size_t BytesPerPixel(gfx::GpuMemoryBuffer::Format format) {
+size_t StrideInBytes(size_t width, gfx::GpuMemoryBuffer::Format format) {
   switch (format) {
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::BGRA_8888:
-      return 4;
+      return width * 4;
     case gfx::GpuMemoryBuffer::RGBX_8888:
       NOTREACHED();
       return 0;
@@ -72,7 +72,7 @@ class GpuMemoryBufferImpl : public gfx::GpuMemoryBuffer {
   bool IsMapped() const override { return mapped_; }
   Format GetFormat() const override { return format_; }
   uint32 GetStride() const override {
-    return size_.width() * BytesPerPixel(format_);
+    return StrideInBytes(size_.width(), format_);
   }
   gfx::GpuMemoryBufferHandle GetHandle() const override {
     NOTREACHED();
@@ -134,7 +134,8 @@ GLManager::~GLManager() {
 scoped_ptr<gfx::GpuMemoryBuffer> GLManager::CreateGpuMemoryBuffer(
     const gfx::Size& size,
     gfx::GpuMemoryBuffer::Format format) {
-  std::vector<unsigned char> data(size.GetArea() * BytesPerPixel(format), 0);
+  std::vector<unsigned char> data(
+      StrideInBytes(size.width(), format) * size.height(), 0);
   scoped_refptr<base::RefCountedBytes> bytes(new base::RefCountedBytes(data));
   return make_scoped_ptr<gfx::GpuMemoryBuffer>(
       new GpuMemoryBufferImpl(bytes.get(), size, format));