3 files changed, 70 insertions, 17 deletions

diff --git a/skia/ext/skia_utils_mac.h b/skia/ext/skia_utils_mac.h
index efa98c0..da290ea 100644
--- a/skia/ext/skia_utils_mac.h
+++ b/skia/ext/skia_utils_mac.h
@@ -9,12 +9,12 @@
 #include <ApplicationServices/ApplicationServices.h>
 #include <vector>
 
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColor.h"
 
 struct SkIRect;
 struct SkPoint;
 struct SkRect;
-class SkBitmap;
 class SkCanvas;
 class SkMatrix;
 #ifdef __LP64__
@@ -108,6 +108,8 @@ class SK_API SkiaBitLocker {
   void releaseIfNeeded();
   SkCanvas* canvas_;
   CGContextRef cgContext_;
+  SkBitmap bitmap_;
+  bool useDeviceBits_;
 };
 
 
diff --git a/skia/ext/skia_utils_mac.mm b/skia/ext/skia_utils_mac.mm
index b227355..f359089 100644
--- a/skia/ext/skia_utils_mac.mm
+++ b/skia/ext/skia_utils_mac.mm
@@ -318,10 +318,15 @@ SkiaBitLocker::~SkiaBitLocker() {
   releaseIfNeeded();
 }
 
+// This must be called to balance calls to cgContext
 void SkiaBitLocker::releaseIfNeeded() {
   if (!cgContext_)
     return;
-  canvas_->getTopDevice()->accessBitmap(true).unlockPixels();
+  if (useDeviceBits_) {
+    bitmap_.unlockPixels();
+  } else {
+    canvas_->drawBitmap(bitmap_, 0, 0);
+  }
   CGContextRelease(cgContext_);
   cgContext_ = 0;
 }
@@ -331,12 +336,20 @@ CGContextRef SkiaBitLocker::cgContext() {
   DCHECK(device);
   if (!device)
     return 0;
-  releaseIfNeeded();
-  const SkBitmap& bitmap = device->accessBitmap(true);
-  bitmap.lockPixels();
-  void* pixels = bitmap.getPixels();
-  cgContext_ = CGBitmapContextCreate(pixels, device->width(),
-    device->height(), 8, bitmap.rowBytes(), CGColorSpaceCreateDeviceRGB(), 
+  releaseIfNeeded(); // This flushes any prior bitmap use
+  const SkBitmap& deviceBits = device->accessBitmap(true);
+  useDeviceBits_ = deviceBits.getPixels();
+  if (useDeviceBits_) {
+    bitmap_ = deviceBits;
+    bitmap_.lockPixels();
+  } else {
+    bitmap_.setConfig(
+        SkBitmap::kARGB_8888_Config, deviceBits.width(), deviceBits.height());
+    bitmap_.allocPixels();
+    bitmap_.eraseColor(0);
+  }
+  cgContext_ = CGBitmapContextCreate(bitmap_.getPixels(), bitmap_.width(),
+    bitmap_.height(), 8, bitmap_.rowBytes(), CGColorSpaceCreateDeviceRGB(), 
     kCGBitmapByteOrder32Host | kCGImageAlphaPremultipliedFirst);
 
   // Apply device matrix.
@@ -345,6 +358,12 @@ CGContextRef SkiaBitLocker::cgContext() {
       -device->height());
   CGContextConcatCTM(cgContext_, contentsTransform);
 
+  // Skip applying the matrix and clip when not writing directly to device.
+  // They're applied in the offscreen case when the bitmap is drawn.
+  if (!useDeviceBits_) {
+    return cgContext_;
+  }
+
   // Apply clip in device coordinates.
   CGMutablePathRef clipPath = CGPathCreateMutable();
   const SkRegion& clipRgn = canvas_->getTotalClip();
diff --git a/skia/ext/skia_utils_mac_unittest.mm b/skia/ext/skia_utils_mac_unittest.mm
index b2175cd..24310b0 100644
--- a/skia/ext/skia_utils_mac_unittest.mm
+++ b/skia/ext/skia_utils_mac_unittest.mm
@@ -25,7 +25,11 @@ class SkiaUtilsMacTest : public testing::Test {
     TestIdentity = 0,
     TestTranslate = 1,
     TestClip = 2,
-    TestXClip = TestTranslate | TestClip
+    TestXClip = TestTranslate | TestClip,
+    TestNoBits = 4,
+    TestTranslateNoBits = TestTranslate | TestNoBits,
+    TestClipNoBits = TestClip | TestNoBits,
+    TestXClipNoBits = TestXClip | TestNoBits,
   };
   void RunBitLockerTest(BitLockerTest test);
 
@@ -119,7 +123,9 @@ void SkiaUtilsMacTest::RunBitLockerTest(BitLockerTest test) {
   memcpy(bits, original, sizeof(original));
   SkBitmap bitmap;
   bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
-  bitmap.setPixels(bits);
+  if (!(test & TestNoBits)) {
+    bitmap.setPixels(bits);
+  }
   SkCanvas canvas;
   canvas.setBitmapDevice(bitmap);
   if (test & TestTranslate)
@@ -128,12 +134,22 @@ void SkiaUtilsMacTest::RunBitLockerTest(BitLockerTest test) {
     SkRect clipRect = {0, height / 2, width, height};
     canvas.clipRect(clipRect);
   }
-  gfx::SkiaBitLocker bitLocker(&canvas);
-  CGContextRef cgContext = bitLocker.cgContext();
-  CGColorRef testColor = CGColorGetConstantColor(kCGColorWhite);
-  CGContextSetFillColorWithColor(cgContext, testColor);
-  CGRect cgRect = {{0, 0}, {width, height}};
-  CGContextFillRect(cgContext, cgRect);
+  {
+    gfx::SkiaBitLocker bitLocker(&canvas);
+    CGContextRef cgContext = bitLocker.cgContext();
+    CGColorRef testColor = CGColorGetConstantColor(kCGColorWhite);
+    CGContextSetFillColorWithColor(cgContext, testColor);
+    CGRect cgRect = {{0, 0}, {width, height}};
+    CGContextFillRect(cgContext, cgRect);
+    if (test & TestNoBits) {
+      bitmap.setPixels(bits);
+      canvas.setBitmapDevice(bitmap);
+      if (test & TestClip) {
+        SkRect clipRect = {0, height / 2, width, height};
+        canvas.clipRect(clipRect);
+      }
+    }
+  }
   const unsigned results[][storageSize] = {
     {0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF}, // identity
     {0xFF333333, 0xFFFFFFFF, 0xFF999999, 0xFFFFFFFF}, // translate
@@ -141,7 +157,7 @@ void SkiaUtilsMacTest::RunBitLockerTest(BitLockerTest test) {
     {0xFF333333, 0xFF666666, 0xFF999999, 0xFFFFFFFF}  // translate | clip
   };
   for (unsigned index = 0; index < storageSize; index++)
-    EXPECT_EQ(results[test][index], bits[index]);
+    EXPECT_EQ(results[test & ~TestNoBits][index], bits[index]);
 }
 
 void SkiaUtilsMacTest::ShapeHelper(int width, int height,
@@ -231,5 +247,21 @@ TEST_F(SkiaUtilsMacTest, BitLocker_XClip) {
   RunBitLockerTest(SkiaUtilsMacTest::TestXClip);
 }
 
+TEST_F(SkiaUtilsMacTest, BitLocker_NoBits) {
+  RunBitLockerTest(SkiaUtilsMacTest::TestNoBits);
+}
+
+TEST_F(SkiaUtilsMacTest, BitLocker_TranslateNoBits) {
+  RunBitLockerTest(SkiaUtilsMacTest::TestTranslateNoBits);
+}
+
+TEST_F(SkiaUtilsMacTest, BitLocker_ClipNoBits) {
+  RunBitLockerTest(SkiaUtilsMacTest::TestClipNoBits);
+}
+
+TEST_F(SkiaUtilsMacTest, BitLocker_XClipNoBits) {
+  RunBitLockerTest(SkiaUtilsMacTest::TestXClipNoBits);
+}
+
 }  // namespace