Add GL_EXT_unpack_subimage support to command buffer client code.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
===================================================================
--- gpu/command_buffer/service/gles2_cmd_decoder.cc	(revision 131422)
+++ gpu/command_buffer/service/gles2_cmd_decoder.cc	(working copy)
@@ -1658,8 +1658,9 @@
   bool success = glGetError() == GL_NO_ERROR;
   if (success) {
     uint32 image_size = 0;
-    GLES2Util::ComputeImageDataSize(
-        size.width(), size.height(), format, GL_UNSIGNED_BYTE, 4, &image_size);
+    GLES2Util::ComputeImageDataSizes(
+        size.width(), size.height(), format, GL_UNSIGNED_BYTE, 4, &image_size,
+        NULL, NULL);
     estimated_size_ = image_size;
     decoder_->UpdateBackbufferMemoryAccounting();
   }
@@ -5972,8 +5973,8 @@
   }
   typedef gles2::ReadPixels::Result Result;
   uint32 pixels_size;
-  if (!GLES2Util::ComputeImageDataSize(
-      width, height, format, type, pack_alignment_, &pixels_size)) {
+  if (!GLES2Util::ComputeImageDataSizes(
+      width, height, format, type, pack_alignment_, &pixels_size, NULL, NULL)) {
     return error::kOutOfBounds;
   }
   void* pixels = GetSharedMemoryAs<void*>(
@@ -6018,27 +6019,20 @@
     // The user requested an out of range area. Get the results 1 line
     // at a time.
     uint32 temp_size;
-    if (!GLES2Util::ComputeImageDataSize(
-        width, 1, format, type, pack_alignment_, &temp_size)) {
+    uint32 unpadded_row_size;
+    uint32 padded_row_size;
+    if (!GLES2Util::ComputeImageDataSizes(
+        width, 2, format, type, pack_alignment_, &temp_size,
+        &unpadded_row_size, &padded_row_size)) {
       SetGLError(GL_INVALID_VALUE, "glReadPixels: dimensions out of range");
       return error::kNoError;
     }
-    GLsizei unpadded_row_size = temp_size;
-    if (!GLES2Util::ComputeImageDataSize(
-        width, 2, format, type, pack_alignment_, &temp_size)) {
-      SetGLError(GL_INVALID_VALUE, "glReadPixels: dimensions out of range");
-      return error::kNoError;
-    }
-    GLsizei padded_row_size = temp_size - unpadded_row_size;
-    if (padded_row_size < 0 || unpadded_row_size < 0) {
-      SetGLError(GL_INVALID_VALUE, "glReadPixels: dimensions out of range");
-      return error::kNoError;
-    }
 
     GLint dest_x_offset = std::max(-x, 0);
     uint32 dest_row_offset;
-    if (!GLES2Util::ComputeImageDataSize(
-      dest_x_offset, 1, format, type, pack_alignment_, &dest_row_offset)) {
+    if (!GLES2Util::ComputeImageDataSizes(
+        dest_x_offset, 1, format, type, pack_alignment_, &dest_row_offset, NULL,
+        NULL)) {
       SetGLError(GL_INVALID_VALUE, "glReadPixels: dimensions out of range");
       return error::kNoError;
     }
@@ -6073,22 +6067,15 @@
     if ((channels_exist & 0x0008) == 0) {
       // Set the alpha to 255 because some drivers are buggy in this regard.
       uint32 temp_size;
-      if (!GLES2Util::ComputeImageDataSize(
-          width, 1, format, type, pack_alignment_, &temp_size)) {
+
+      uint32 unpadded_row_size;
+      uint32 padded_row_size;
+      if (!GLES2Util::ComputeImageDataSizes(
+          width, 2, format, type, pack_alignment_, &temp_size,
+          &unpadded_row_size, &padded_row_size)) {
         SetGLError(GL_INVALID_VALUE, "glReadPixels: dimensions out of range");
         return error::kNoError;
       }
-      GLsizei unpadded_row_size = temp_size;
-      if (!GLES2Util::ComputeImageDataSize(
-          width, 2, format, type, pack_alignment_, &temp_size)) {
-        SetGLError(GL_INVALID_VALUE, "glReadPixels: dimensions out of range");
-        return error::kNoError;
-      }
-      GLsizei padded_row_size = temp_size - unpadded_row_size;
-      if (padded_row_size < 0 || unpadded_row_size < 0) {
-        SetGLError(GL_INVALID_VALUE, "glReadPixels: dimensions out of range");
-        return error::kNoError;
-      }
       // NOTE: Assumes the type is GL_UNSIGNED_BYTE which was true at the time
       // of this implementation.
       if (type != GL_UNSIGNED_BYTE) {
@@ -6464,8 +6451,9 @@
     bool is_texture_immutable) {
   // Assumes the size has already been checked.
   uint32 pixels_size = 0;
-  if (!GLES2Util::ComputeImageDataSize(
-      width, height, format, type, unpack_alignment_, &pixels_size)) {
+  if (!GLES2Util::ComputeImageDataSizes(
+      width, height, format, type, unpack_alignment_, &pixels_size, NULL,
+      NULL)) {
     return false;
   }
   scoped_array<char> zero(new char[pixels_size]);
@@ -6772,8 +6760,9 @@
   uint32 pixels_shm_id = static_cast<uint32>(c.pixels_shm_id);
   uint32 pixels_shm_offset = static_cast<uint32>(c.pixels_shm_offset);
   uint32 pixels_size;
-  if (!GLES2Util::ComputeImageDataSize(
-      width, height, format, type, unpack_alignment_, &pixels_size)) {
+  if (!GLES2Util::ComputeImageDataSizes(
+      width, height, format, type, unpack_alignment_, &pixels_size, NULL,
+      NULL)) {
     return error::kOutOfBounds;
   }
   const void* pixels = NULL;
@@ -6800,8 +6789,8 @@
   GLenum format = static_cast<GLenum>(c.format);
   GLenum type = static_cast<GLenum>(c.type);
   uint32 size;
-  if (!GLES2Util::ComputeImageDataSize(
-      width, height, format, type, unpack_alignment_, &size)) {
+  if (!GLES2Util::ComputeImageDataSizes(
+      width, height, format, type, unpack_alignment_, &size, NULL, NULL)) {
     return error::kOutOfBounds;
   }
   const void* pixels = GetImmediateDataAs<const void*>(
@@ -7027,8 +7016,9 @@
       copyHeight != height) {
     // some part was clipped so clear the sub rect.
     uint32 pixels_size = 0;
-    if (!GLES2Util::ComputeImageDataSize(
-        width, height, format, type, unpack_alignment_, &pixels_size)) {
+    if (!GLES2Util::ComputeImageDataSizes(
+        width, height, format, type, unpack_alignment_, &pixels_size, NULL,
+        NULL)) {
       SetGLError(GL_INVALID_VALUE, "glCopyTexSubImage2D: dimensions too large");
       return;
     }
@@ -7135,8 +7125,8 @@
   GLenum format = static_cast<GLenum>(c.format);
   GLenum type = static_cast<GLenum>(c.type);
   uint32 data_size;
-  if (!GLES2Util::ComputeImageDataSize(
-      width, height, format, type, unpack_alignment_, &data_size)) {
+  if (!GLES2Util::ComputeImageDataSizes(
+      width, height, format, type, unpack_alignment_, &data_size, NULL, NULL)) {
     return error::kOutOfBounds;
   }
   const void* pixels = GetSharedMemoryAs<const void*>(
@@ -7184,8 +7174,8 @@
   GLenum format = static_cast<GLenum>(c.format);
   GLenum type = static_cast<GLenum>(c.type);
   uint32 data_size;
-  if (!GLES2Util::ComputeImageDataSize(
-      width, height, format, type, unpack_alignment_, &data_size)) {
+  if (!GLES2Util::ComputeImageDataSizes(
+      width, height, format, type, unpack_alignment_, &data_size, NULL, NULL)) {
     return error::kOutOfBounds;
   }
   const void* pixels = GetImmediateDataAs<const void*>(