GpuMemoryBuffer interface change: Map(**) --> Map() + memory(plane); GetStride(*) --> stride(plane)

And at the same time clean up/simplify/homogeneise
uses of those APIs.

buffer_format_util.cc:RowSizeForBufferFormatChecked()
is only used in unittests and internally to the file, this CL
restricts it to the .cc file. Also a function there is only
used in test --> added ForTesting() suffix.

BUG=542225
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1401183003

Cr-Commit-Position: refs/heads/master@{#355396}

3 files changed, 112 insertions, 75 deletions

diff --git a/ui/gfx/buffer_format_util.cc b/ui/gfx/buffer_format_util.cc
index 33bf627..704b680 100644
--- a/ui/gfx/buffer_format_util.cc
+++ b/ui/gfx/buffer_format_util.cc
@@ -23,9 +23,60 @@ static_assert(arraysize(kBufferFormats) ==
                   (static_cast<int>(BufferFormat::LAST) + 1),
               "BufferFormat::LAST must be last value of kBufferFormats");
 
+
+bool RowSizeForBufferFormatChecked(
+    size_t width, BufferFormat format, int plane, size_t* size_in_bytes) {
+  base::CheckedNumeric<size_t> checked_size = width;
+  switch (format) {
+    case BufferFormat::ATCIA:
+    case BufferFormat::DXT5:
+      DCHECK_EQ(0, plane);
+      *size_in_bytes = width;
+      return true;
+    case BufferFormat::ATC:
+    case BufferFormat::DXT1:
+    case BufferFormat::ETC1:
+      DCHECK_EQ(0, plane);
+      DCHECK_EQ(0u, width % 2);
+      *size_in_bytes = width / 2;
+      return true;
+    case BufferFormat::R_8:
+      checked_size += 3;
+      if (!checked_size.IsValid())
+        return false;
+      *size_in_bytes = checked_size.ValueOrDie() & ~0x3;
+      return true;
+    case BufferFormat::RGBA_4444:
+    case BufferFormat::UYVY_422:
+      checked_size *= 2;
+      if (!checked_size.IsValid())
+        return false;
+      *size_in_bytes = checked_size.ValueOrDie();
+      return true;
+    case BufferFormat::BGRX_8888:
+    case BufferFormat::RGBA_8888:
+    case BufferFormat::BGRA_8888:
+      checked_size *= 4;
+      if (!checked_size.IsValid())
+        return false;
+      *size_in_bytes = checked_size.ValueOrDie();
+      return true;
+    case BufferFormat::YUV_420:
+      DCHECK_EQ(0u, width % 2);
+      *size_in_bytes = width / SubsamplingFactorForBufferFormat(format, plane);
+      return true;
+    case BufferFormat::YUV_420_BIPLANAR:
+      DCHECK_EQ(width % 2, 0u);
+      *size_in_bytes = width;
+      return true;
+  }
+  NOTREACHED();
+  return false;
+}
+
 }  // namespace
 
-std::vector<BufferFormat> GetBufferFormats() {
+std::vector<BufferFormat> GetBufferFormatsForTesting() {
   return std::vector<BufferFormat>(kBufferFormats,
                                    kBufferFormats + arraysize(kBufferFormats));
 }
@@ -72,7 +123,7 @@ size_t SubsamplingFactorForBufferFormat(BufferFormat format, int plane) {
       DCHECK_LT(static_cast<size_t>(plane), arraysize(factor));
       return factor[plane];
     }
-    case gfx::BufferFormat::YUV_420_BIPLANAR: {
+    case BufferFormat::YUV_420_BIPLANAR: {
       static size_t factor[] = {1, 2};
       DCHECK_LT(static_cast<size_t>(plane), arraysize(factor));
       return factor[plane];
@@ -89,66 +140,16 @@ size_t RowSizeForBufferFormat(size_t width, BufferFormat format, int plane) {
   return row_size;
 }
 
-bool RowSizeForBufferFormatChecked(
-    size_t width, BufferFormat format, int plane, size_t* size_in_bytes) {
-  base::CheckedNumeric<size_t> checked_size = width;
-  switch (format) {
-    case BufferFormat::ATCIA:
-    case BufferFormat::DXT5:
-      DCHECK_EQ(0, plane);
-      *size_in_bytes = width;
-      return true;
-    case BufferFormat::ATC:
-    case BufferFormat::DXT1:
-    case BufferFormat::ETC1:
-      DCHECK_EQ(0, plane);
-      DCHECK_EQ(0u, width % 2);
-      *size_in_bytes = width / 2;
-      return true;
-    case BufferFormat::R_8:
-      checked_size += 3;
-      if (!checked_size.IsValid())
-        return false;
-      *size_in_bytes = checked_size.ValueOrDie() & ~0x3;
-      return true;
-    case BufferFormat::RGBA_4444:
-    case BufferFormat::UYVY_422:
-      checked_size *= 2;
-      if (!checked_size.IsValid())
-        return false;
-      *size_in_bytes = checked_size.ValueOrDie();
-      return true;
-    case BufferFormat::BGRX_8888:
-    case BufferFormat::RGBA_8888:
-    case BufferFormat::BGRA_8888:
-      checked_size *= 4;
-      if (!checked_size.IsValid())
-        return false;
-      *size_in_bytes = checked_size.ValueOrDie();
-      return true;
-    case BufferFormat::YUV_420:
-      DCHECK_EQ(0u, width % 2);
-      *size_in_bytes = width / SubsamplingFactorForBufferFormat(format, plane);
-      return true;
-    case gfx::BufferFormat::YUV_420_BIPLANAR:
-      DCHECK_EQ(width % 2, 0u);
-      *size_in_bytes = width;
-      return true;
-  }
-  NOTREACHED();
-  return false;
-}
-
-size_t BufferSizeForBufferFormat(
-    const Size& size, BufferFormat format) {
+size_t BufferSizeForBufferFormat(const Size& size, BufferFormat format) {
   size_t buffer_size = 0;
   bool valid = BufferSizeForBufferFormatChecked(size, format, &buffer_size);
   DCHECK(valid);
   return buffer_size;
 }
 
-bool BufferSizeForBufferFormatChecked(
-    const Size& size, BufferFormat format, size_t* size_in_bytes) {
+bool BufferSizeForBufferFormatChecked(const Size& size,
+                                      BufferFormat format,
+                                      size_t* size_in_bytes) {
   base::CheckedNumeric<size_t> checked_size = 0;
   size_t num_planes = NumberOfPlanesForBufferFormat(format);
   for (size_t i = 0; i < num_planes; ++i) {
@@ -168,4 +169,38 @@ bool BufferSizeForBufferFormatChecked(
   return true;
 }
 
+int BufferOffsetForBufferFormat(const Size& size,
+                                BufferFormat format,
+                                size_t plane) {
+  DCHECK_LT(plane, gfx::NumberOfPlanesForBufferFormat(format));
+  switch (format) {
+    case BufferFormat::ATC:
+    case BufferFormat::ATCIA:
+    case BufferFormat::DXT1:
+    case BufferFormat::DXT5:
+    case BufferFormat::ETC1:
+    case BufferFormat::R_8:
+    case BufferFormat::RGBA_4444:
+    case BufferFormat::RGBA_8888:
+    case BufferFormat::BGRX_8888:
+    case BufferFormat::BGRA_8888:
+    case BufferFormat::UYVY_422:
+      return 0;
+    case BufferFormat::YUV_420: {
+      static size_t offset_in_2x2_sub_sampling_sizes[] = {0, 4, 5};
+      DCHECK_LT(plane, arraysize(offset_in_2x2_sub_sampling_sizes));
+      return offset_in_2x2_sub_sampling_sizes[plane] *
+             (size.width() / 2 + size.height() / 2);
+    }
+    case gfx::BufferFormat::YUV_420_BIPLANAR: {
+      static size_t offset_in_2x2_sub_sampling_sizes[] = {0, 4};
+      DCHECK_LT(plane, arraysize(offset_in_2x2_sub_sampling_sizes));
+      return offset_in_2x2_sub_sampling_sizes[plane] *
+             (size.width() / 2 + size.height() / 2);
+    }
+  }
+  NOTREACHED();
+  return 0;
+}
+
 }  // namespace gfx
diff --git a/ui/gfx/buffer_format_util.h b/ui/gfx/buffer_format_util.h
index f656f4a..4e42039 100644
--- a/ui/gfx/buffer_format_util.h
+++ b/ui/gfx/buffer_format_util.h
@@ -15,26 +15,21 @@
 namespace gfx {
 
 // Returns a vector containing all buffer formats.
-GFX_EXPORT std::vector<BufferFormat> GetBufferFormats();
+GFX_EXPORT std::vector<BufferFormat> GetBufferFormatsForTesting();
 
 // Returns the number of planes for |format|.
 GFX_EXPORT size_t NumberOfPlanesForBufferFormat(BufferFormat format);
 
 // Returns the subsampling factor applied to the given zero-indexed |plane| of
 // |format| both horizontally and vertically.
-GFX_EXPORT size_t SubsamplingFactorForBufferFormat(
-    BufferFormat format, int plane);
+GFX_EXPORT size_t SubsamplingFactorForBufferFormat(BufferFormat format,
+                                                   int plane);
 
 // Returns the number of bytes used to store a row of the given zero-indexed
 // |plane| of |format|.
 GFX_EXPORT size_t RowSizeForBufferFormat(size_t width,
                                          BufferFormat format,
                                          int plane);
-GFX_EXPORT bool RowSizeForBufferFormatChecked(size_t width,
-                                              BufferFormat format,
-                                              int plane,
-                                              size_t* size_in_bytes)
-    WARN_UNUSED_RESULT;
 
 // Returns the number of bytes used to store all the planes of a given |format|.
 GFX_EXPORT size_t BufferSizeForBufferFormat(const Size& size,
@@ -44,6 +39,10 @@ GFX_EXPORT bool BufferSizeForBufferFormatChecked(const Size& size,
                                                  size_t* size_in_bytes)
     WARN_UNUSED_RESULT;
 
+GFX_EXPORT int BufferOffsetForBufferFormat(const Size& size,
+                                           BufferFormat format,
+                                           size_t plane);
+
 }  // namespace gfx
 
 #endif  // UI_GFX_BUFFER_FORMAT_UTIL_H_
diff --git a/ui/gfx/gpu_memory_buffer.h b/ui/gfx/gpu_memory_buffer.h
index 629dabc..72ff1d2 100644
--- a/ui/gfx/gpu_memory_buffer.h
+++ b/ui/gfx/gpu_memory_buffer.h
@@ -30,7 +30,7 @@ enum GpuMemoryBufferType {
   GPU_MEMORY_BUFFER_TYPE_LAST = OZONE_NATIVE_PIXMAP
 };
 
-using GpuMemoryBufferId = gfx::GenericSharedMemoryId;
+using GpuMemoryBufferId = GenericSharedMemoryId;
 
 struct GFX_EXPORT GpuMemoryBufferHandle {
   GpuMemoryBufferHandle();
@@ -55,25 +55,28 @@ class GFX_EXPORT GpuMemoryBuffer {
   virtual ~GpuMemoryBuffer() {}
 
   // Maps each plane of the buffer into the client's address space so it can be
-  // written to by the CPU. A pointer to plane K is stored at index K-1 of the
-  // |data| array. This call may block, for instance if the GPU needs to finish
-  // accessing the buffer or if CPU caches need to be synchronized. Returns
-  // false on failure.
-  virtual bool Map(void** data) = 0;
-
-  // Unmaps the buffer. It's illegal to use the pointer returned by Map() after
-  // this has been called.
+  // written to by the CPU. This call may block, for instance if the GPU needs
+  // to finish accessing the buffer or if CPU caches need to be synchronized.
+  // Returns false on failure.
+  virtual bool Map() = 0;
+
+  // Returns a pointer to the memory address of a plane. Buffer must have been
+  // successfully mapped using a call to Map() before calling this function.
+  virtual void* memory(size_t plane) = 0;
+
+  // Unmaps the buffer. It's illegal to use any pointer returned by memory()
+  // after this has been called.
   virtual void Unmap() = 0;
 
   // Returns the size for the buffer.
-  virtual gfx::Size GetSize() const = 0;
+  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 void GetStride(int* stride) const = 0;
+  virtual int stride(size_t plane) const = 0;
 
   // Returns a unique identifier associated with buffer.
   virtual GpuMemoryBufferId GetId() const = 0;