Update from https://crrev.com/306655

skia/ext/analysis_canvas.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "skia/ext/analysis_canvas.h"
 #include "third_party/skia/include/core/SkDraw.h"
 #include "third_party/skia/include/core/SkRRect.h"
 #include "third_party/skia/include/core/SkShader.h"
 #include "third_party/skia/src/core/SkRasterClip.h"
 #include "ui/gfx/rect_conversions.h"
 
 namespace {
 
 const int kNoLayer = -1;
 
+bool ActsLikeClear(SkXfermode::Mode mode, unsigned src_alpha) {
+  switch (mode) {
+    case SkXfermode::kClear_Mode:
+      return true;
+    case SkXfermode::kSrc_Mode:
+    case SkXfermode::kSrcIn_Mode:
+    case SkXfermode::kDstIn_Mode:
+    case SkXfermode::kSrcOut_Mode:
+    case SkXfermode::kDstATop_Mode:
+      return src_alpha == 0;
+    case SkXfermode::kDstOut_Mode:
+      return src_alpha == 0xFF;
+    default:
+      return false;
+  }
+}
+
 bool IsSolidColorPaint(const SkPaint& paint) {
   SkXfermode::Mode xfermode;
 
   // getXfermode can return a NULL, but that is handled
   // gracefully by AsMode (NULL turns into kSrcOver mode).
   SkXfermode::AsMode(paint.getXfermode(), &xfermode);
 
   // Paint is solid color if the following holds:
   // - Alpha is 1.0, style is fill, and there are no special effects
   // - Xfer mode is either kSrc or kSrcOver (kSrcOver is equivalent
@@ skipping 55 matching lines @@
 
   if (!is_forced_not_solid_ && SkColorGetA(color) == 255) {
     is_solid_color_ = true;
     color_ = color;
   } else {
     is_solid_color_ = false;
   }
 }
 
 void AnalysisCanvas::drawPaint(const SkPaint& paint) {
-  // This check is in SkCanvas::drawPaint(), and some of our unittests rely on
-  // on this, so we reproduce it here.
-  if (isClipEmpty())
-    return;
-
-  is_solid_color_ = false;
-  is_transparent_ = false;
-  ++draw_op_count_;
+  SkRect rect;
+  getClipBounds(&rect);
+  drawRect(rect, paint);
 }
 
 void AnalysisCanvas::drawPoints(SkCanvas::PointMode mode,
                                 size_t count,
                                 const SkPoint points[],
                                 const SkPaint& paint) {
   is_solid_color_ = false;
   is_transparent_ = false;
   ++draw_op_count_;
 }
@@ skipping 19 matching lines @@
   // - The quad is a full tile quad
   // - We're not in "forced not transparent" mode
   // - Transfer mode is clear (0 color, 0 alpha)
   //
   // If the paint alpha is not 0, or if the transfrer mode is
   // not src, then this canvas will not be transparent.
   //
   // In all other cases, we keep the current transparent value
   if (does_cover_canvas &&
       !is_forced_not_transparent_ &&
-      xfermode == SkXfermode::kClear_Mode) {
+      ActsLikeClear(xfermode, paint.getAlpha())) {
     is_transparent_ = true;
   } else if (paint.getAlpha() != 0 || xfermode != SkXfermode::kSrc_Mode) {
     is_transparent_ = false;
   }
 
   // This bitmap is solid if and only if the following holds.
   // Note that this might be overly conservative:
   // - We're not in "forced not solid" mode
   // - Paint is solid color
   // - The quad is a full tile quad
@@ skipping 301 matching lines @@
       force_not_transparent_stack_level_ = kNoLayer;
     }
   }
 
   INHERITED::willRestore();
 }
 
 }  // namespace skia