Allow binding multiple textures to one DC Layer overlay.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index db2c9d22c142c3fa90d8e93ba069e37e30e79b9b..a66d8774d679586d76dbcb0bb6923b234bfa6da3 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -12110,38 +12110,62 @@ error::Error GLES2DecoderImpl::HandleScheduleDCLayerCHROMIUM(
     return error::kNoError;
   }
 
-  gl::GLImage* image = nullptr;
-  GLuint contents_texture_id = c.contents_texture_id;
-  if (contents_texture_id) {
-    TextureRef* ref = texture_manager()->GetTexture(contents_texture_id);
-    if (!ref) {
-      LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, "glScheduleDCLayerCHROMIUM",
-                         "unknown texture");
-      return error::kNoError;
-    }
-    Texture::ImageState image_state;
-    image = ref->texture()->GetLevelImage(ref->texture()->target(), 0,
-                                          &image_state);
-    if (!image) {
-      LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, "glScheduleDCLayerCHROMIUM",
-                         "unsupported texture format");
-      return error::kNoError;
-    }
+  GLsizei num_textures = c.num_textures;
+  if (num_textures < 0 || num_textures > 4) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "glScheduleDCLayerCHROMIUM",
+                       "number of textures greater than maximum of 4");
+    return error::kNoError;
   }
 
-  const GLfloat* mem = GetSharedMemoryAs<const GLfloat*>(c.shm_id, c.shm_offset,
-                                                         8 * sizeof(GLfloat));
-  if (!mem) {
+  size_t textures_size = num_textures * sizeof(GLuint);
+
+  base::CheckedNumeric<uint32_t> data_size = textures_size;
+  const uint32_t kRectDataSize = 8 * sizeof(GLfloat);
+  data_size += kRectDataSize;
+  if (!data_size.IsValid())
+    return error::kOutOfBounds;
+  const void* data =
+      GetAddressAndCheckSize(c.shm_id, c.shm_offset, data_size.ValueOrDie());
+  if (!data) {
     return error::kOutOfBounds;
   }
+  const GLfloat* mem = reinterpret_cast<const GLfloat*>(data);
+
   gfx::RectF contents_rect(mem[0], mem[1], mem[2], mem[3]);
   gfx::RectF bounds_rect(mem[4], mem[5], mem[6], mem[7]);
 
+  const volatile GLuint* texture_ids = reinterpret_cast<const volatile GLuint*>(
+      static_cast<const volatile char*>(data) + kRectDataSize);
+
+  std::vector<scoped_refptr<gl::GLImage>> images;
+  for (int i = 0; i < num_textures; ++i) {
+    GLuint contents_texture_id = texture_ids[i];
+    scoped_refptr<gl::GLImage> image;
+    if (contents_texture_id) {
+      TextureRef* ref = texture_manager()->GetTexture(contents_texture_id);
+      if (!ref) {
+        LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, "glScheduleDCLayerCHROMIUM",
+                           "unknown texture");
+        return error::kNoError;
+      }
+      Texture::ImageState image_state;
+      image = ref->texture()->GetLevelImage(ref->texture()->target(), 0,
+                                            &image_state);
+      if (!image) {
+        LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, "glScheduleDCLayerCHROMIUM",
+                           "unsupported texture format");
+        return error::kNoError;
+      }
+    }
+    images.push_back(image);
+  }
+
   ui::DCRendererLayerParams params = ui::DCRendererLayerParams(
       dc_layer_shared_state_->is_clipped, dc_layer_shared_state_->clip_rect,
-      dc_layer_shared_state_->z_order, dc_layer_shared_state_->transform, image,
-      contents_rect, gfx::ToEnclosingRect(bounds_rect), c.background_color,
-      c.edge_aa_mask, dc_layer_shared_state_->opacity, filter);
+      dc_layer_shared_state_->z_order, dc_layer_shared_state_->transform,
+      images, contents_rect, gfx::ToEnclosingRect(bounds_rect),
+      c.background_color, c.edge_aa_mask, dc_layer_shared_state_->opacity,
+      filter);
   if (!surface_->ScheduleDCLayer(params)) {
     LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "glScheduleDCLayerCHROMIUM",
                        "failed to schedule DCLayer");