Fix crash in the ThreadedIconLoader.

Crash reports show that this was happening in the SkBitmap's copy
constructor, which likely means that the Resize image operation
sometimes returns a null icon. This CL adds an extra check.

Bug: 1003293
Change-Id: If26c5a9a2690a6d0124dc2b7fcaaa487681dafce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1805654
Auto-Submit: Rayan Kanso <rayankans@chromium.org>
Commit-Queue: Nate Chapin <japhet@chromium.org>
Reviewed-by: Nate Chapin <japhet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#701186}

third_party/blink/renderer/core/loader/threaded_icon_loader.cc

@@ -152,10 +152,16 @@ void ThreadedIconLoader::DecodeAndResizeImageOnBackgroundThread(
   // Use the RESIZE_GOOD quality allowing the implementation to pick an
   // appropriate method for the resize. Can be increased to RESIZE_BETTER
   // or RESIZE_BEST if the quality looks poor.
-  decoded_icon_ = skia::ImageOperations::Resize(
+  SkBitmap resized_icon = skia::ImageOperations::Resize(
       decoded_icon_, skia::ImageOperations::RESIZE_GOOD, resized_width,
       resized_height);
 
+  if (resized_icon.isNull()) {
+    notify_complete(1.0);
+    return;
+  }
+
+  decoded_icon_ = std::move(resized_icon);
   notify_complete(scale);
 }
 

third_party/blink/renderer/core/loader/threaded_icon_loader_test.cc

@@ -137,5 +137,18 @@ TEST_F(ThreadedIconLoaderTest, LoadTimeRecordedByUMA) {
   histogram_tester.ExpectTotalCount("Blink.ThreadedIconLoader.LoadTime", 1);
 }
 
+TEST_F(ThreadedIconLoaderTest, ResizeFailed) {
+  WebSize dimensions = {25, 0};
+  auto result = LoadIcon(RegisterMockedURL(kIconLoaderIcon100x100), dimensions);
+  const SkBitmap& icon = result.first;
+  double resize_scale = result.second;
+
+  // Resizing should have failed so the original will be returned.
+  ASSERT_FALSE(icon.isNull());
+  EXPECT_EQ(icon.width(), 100);
+  EXPECT_EQ(icon.height(), 100);
+  EXPECT_EQ(resize_scale, 1.0);
+}
+
 }  // namespace
 }  // namespace blink