Add R_8 GPU memory buffers format.

content/common/gpu/client/gpu_memory_buffer_impl.cc

Index: content/common/gpu/client/gpu_memory_buffer_impl.cc
diff --git a/content/common/gpu/client/gpu_memory_buffer_impl.cc b/content/common/gpu/client/gpu_memory_buffer_impl.cc
index 208261dd0831e940f8f858b63a4169888c706db8..dc6ade5ed9d76287cff97119ea1657d117e1d65a 100644
--- a/content/common/gpu/client/gpu_memory_buffer_impl.cc
+++ b/content/common/gpu/client/gpu_memory_buffer_impl.cc
@@ -80,33 +80,33 @@ GpuMemoryBufferImpl* GpuMemoryBufferImpl::FromClientBuffer(
 bool GpuMemoryBufferImpl::StrideInBytes(size_t width,
                                         Format format,
                                         size_t* stride_in_bytes) {
-  base::CheckedNumeric<size_t> s = width;
+  base::CheckedNumeric<size_t> checked_stride = width;
   switch (format) {
-    case ATCIA:
-    case DXT5:
+    case GpuMemoryBuffer::R_8:
+      checked_stride += 3;
+      if (!checked_stride.IsValid())
+        return false;
+      *stride_in_bytes = checked_stride.ValueOrDie() & ~0x3;
+      return true;
+    case GpuMemoryBuffer::ATCIA:
+    case GpuMemoryBuffer::DXT5:
       *stride_in_bytes = width;
       return true;
-    case ATC:
-    case DXT1:
-    case ETC1:
-      DCHECK_EQ(width % 2, 0U);
-      s /= 2;
-      if (!s.IsValid())
-        return false;
-
-      *stride_in_bytes = s.ValueOrDie();
+    case GpuMemoryBuffer::ATC:
+    case GpuMemoryBuffer::DXT1:
+    case GpuMemoryBuffer::ETC1:
+      DCHECK_EQ(width % 2, 0u);
+      *stride_in_bytes = width / 2;
       return true;
-    case RGBA_8888:
-    case RGBX_8888:
-    case BGRA_8888:
-      s *= 4;
-      if (!s.IsValid())
+    case GpuMemoryBuffer::RGBA_8888:
+    case GpuMemoryBuffer::RGBX_8888:
+    case GpuMemoryBuffer::BGRA_8888:
+      checked_stride *= 4;
+      if (!checked_stride.IsValid())
         return false;
-
-      *stride_in_bytes = s.ValueOrDie();
+      *stride_in_bytes = checked_stride.ValueOrDie();
       return true;
   }
-
   NOTREACHED();
   return false;
 }
@@ -120,6 +120,7 @@ size_t GpuMemoryBufferImpl::NumberOfPlanesForGpuMemoryBufferFormat(
     case gfx::GpuMemoryBuffer::Format::DXT1:
     case gfx::GpuMemoryBuffer::Format::DXT5:
     case gfx::GpuMemoryBuffer::Format::ETC1:
+    case gfx::GpuMemoryBuffer::Format::R_8:
     case gfx::GpuMemoryBuffer::Format::RGBA_8888:
     case gfx::GpuMemoryBuffer::Format::RGBX_8888:
     case gfx::GpuMemoryBuffer::Format::BGRA_8888: