Use skia.mojom.BitmapN32 in FrameWidget mojoms

These bitmaps are safer for transport from untrustworthy sources since
all bitmaps should be in N32 format and the browser can make bad
assumptions as a result.

Bug: 1144462
Change-Id: I9c4fde80a4124753c11845cbcc202cce2c3d31a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2582928Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835684}

content/browser/renderer_host/render_view_host_unittest.cc

@@ -104,7 +104,6 @@ class MockDraggingRenderViewHostDelegateView
                      RenderWidgetHostImpl* source_rwh) override {
     drag_url_ = drop_data.url;
     html_base_url_ = drop_data.html_base_url;
-    image_ = image;
   }
 
   GURL drag_url() {
@@ -115,12 +114,9 @@ class MockDraggingRenderViewHostDelegateView
     return html_base_url_;
   }
 
-  const gfx::ImageSkia& image() { return image_; }
-
  private:
   GURL drag_url_;
   GURL html_base_url_;
-  gfx::ImageSkia image_;
 };
 
 TEST_F(RenderViewHostTest, StartDragging) {
@@ -163,37 +159,6 @@ TEST_F(RenderViewHostTest, StartDragging) {
   EXPECT_EQ(http_url, delegate_view.html_base_url());
 }
 
-TEST_F(RenderViewHostTest, StartDraggingWithInvalidBitmap) {
-  TestWebContents* web_contents = contents();
-  MockDraggingRenderViewHostDelegateView delegate_view;
-  web_contents->set_delegate_view(&delegate_view);
-
-  GURL http_url = GURL("http://www.domain.com/index.html");
-
-  DropData drop_data;
-  // If `html` is not populated, `html_base_url` won't be populated when
-  // converting to `DragData` with `DropDataToDragData`.
-  drop_data.html = base::string16();
-  drop_data.url = http_url;
-  drop_data.html_base_url = http_url;
-
-  SkBitmap badbitmap;
-  badbitmap.allocPixels(
-      SkImageInfo::Make(1, 1, kARGB_4444_SkColorType, kPremul_SkAlphaType));
-  badbitmap.eraseColor(SK_ColorGREEN);
-
-  SkBitmap n32bitmap;
-  EXPECT_TRUE(skia::SkBitmapToN32OpaqueOrPremul(badbitmap, &n32bitmap));
-
-  // An N32 bitmap is a valid drag image.
-  test_rvh()->TestStartDragging(drop_data, n32bitmap);
-  EXPECT_TRUE(gfx::BitmapsAreEqual(n32bitmap, *delegate_view.image().bitmap()));
-
-  // Other bitmap types are not, and are converted.
-  test_rvh()->TestStartDragging(drop_data, badbitmap);
-  EXPECT_TRUE(gfx::BitmapsAreEqual(n32bitmap, *delegate_view.image().bitmap()));
-}
-
 TEST_F(RenderViewHostTest, DragEnteredFileURLsStillBlocked) {
   DropData dropped_data;
   gfx::PointF client_point;

content/browser/renderer_host/render_widget_host_impl.cc

@@ -2549,7 +2549,7 @@ void RenderWidgetHostImpl::DidFirstVisuallyNonEmptyPaint() {
 void RenderWidgetHostImpl::StartDragging(
     blink::mojom::DragDataPtr drag_data,
     blink::DragOperationsMask drag_operations_mask,
-    const SkBitmap& unsafe_bitmap,
+    const SkBitmap& bitmap,
     const gfx::Vector2d& bitmap_offset_in_dip,
     blink::mojom::DragEventSourceInfoPtr event_info) {
   RenderViewHostDelegateView* view = delegate_->GetDelegateView();
@@ -2558,16 +2558,6 @@ void RenderWidgetHostImpl::StartDragging(
     DragSourceSystemDragEnded();
     return;
   }
-  SkBitmap bitmap;
-  // On receipt of an arbitrary bitmap from the renderer, we convert to an N32
-  // 32bpp bitmap. Other pixel sizes can lead to out-of-bounds mistakes when
-  // transferring the pixels out of the/ bitmap into other buffers.
-  if (!skia::SkBitmapToN32OpaqueOrPremul(unsafe_bitmap, &bitmap)) {
-    NOTREACHED() << "Unable to convert bitmap for drag-and-drop";
-    // Need to clear drag and drop state in blink.
-    DragSourceSystemDragEnded();
-    return;
-  }
 
   DropData drop_data = DragDataToDropData(*drag_data);
   DropData filtered_data(drop_data);

third_party/blink/public/mojom/page/widget.mojom

@@ -190,7 +190,7 @@ interface FrameWidgetHost {
   // session at the OS level.
   StartDragging(DragData drag_data,
                 AllowedDragOperations operations_allowed,
-                skia.mojom.BitmapWithArbitraryBpp? image,
+                skia.mojom.BitmapN32? image,
                 gfx.mojom.Vector2d bitmap_offset_in_dip,
                 DragEventSourceInfo event_info);
 };