gfx: Use unsigned strides for gpu memory buffers.

ui/gfx/gpu_memory_buffer.h

 // Copyright 2013 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.
 
 #ifndef UI_GFX_GPU_MEMORY_BUFFER_H_
 #define UI_GFX_GPU_MEMORY_BUFFER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 30 matching lines @@
 
 struct GFX_EXPORT GpuMemoryBufferHandle {
   GpuMemoryBufferHandle();
   GpuMemoryBufferHandle(const GpuMemoryBufferHandle& other);
   ~GpuMemoryBufferHandle();
   bool is_null() const { return type == EMPTY_BUFFER; }
   GpuMemoryBufferType type;
   GpuMemoryBufferId id;
   base::SharedMemoryHandle handle;
   uint32_t offset;
-  int32_t stride;
+  uint32_t stride;
 #if defined(USE_OZONE)
   NativePixmapHandle native_pixmap_handle;
 #elif defined(OS_MACOSX) && !defined(OS_IOS)
   ScopedRefCountedIOSurfaceMachPort mach_port;
 #endif
 };
 
 base::trace_event::MemoryAllocatorDumpGuid GFX_EXPORT
 GetGpuMemoryBufferGUIDForTracing(uint64_t tracing_process_id,
                                  GpuMemoryBufferId buffer_id);
@@ skipping 20 matching lines @@
   virtual void Unmap() = 0;
 
   // Returns the size for the buffer.
   virtual Size GetSize() const = 0;
 
   // Returns the format for the buffer.
   virtual BufferFormat GetFormat() const = 0;
 
   // Fills the stride in bytes for each plane of the buffer. The stride of
   // plane K is stored at index K-1 of the |stride| array.
-  virtual int stride(size_t plane) const = 0;
+  virtual uint32_t stride(size_t plane) const = 0;
 
   // Set the color space in which this buffer should be interpreted when used
   // for scanout. Note that this will not impact texturing from the buffer.
   virtual void SetColorSpaceForScanout(const gfx::ColorSpace& color_space);
 
   // Returns a unique identifier associated with buffer.
   virtual GpuMemoryBufferId GetId() const = 0;
 
   // Returns a platform specific handle for this buffer.
   virtual GpuMemoryBufferHandle GetHandle() const = 0;
 
   // Type-checking downcast routine.
   virtual ClientBuffer AsClientBuffer() = 0;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GPU_MEMORY_BUFFER_H_