2 files changed, 33 insertions, 7 deletions
diff --git a/src/core/SkBitmapDevice.cpp b/src/core/SkBitmapDevice.cpp
index b7df9a4c25..ac3b9df082 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -8,6 +8,7 @@
 #include "SkBitmapDevice.h"
 #include "SkConfig8888.h"
 #include "SkDraw.h"
+#include "SkMallocPixelRef.h"
 #include "SkMatrix.h"
 #include "SkPaint.h"
 #include "SkPath.h"
@@ -94,12 +95,18 @@ SkBitmapDevice* SkBitmapDevice::Create(const SkImageInfo& origInfo,
         if (!bitmap.setInfo(info)) {
             return nullptr;
         }
-    } else {
+    } else if (bitmap.info().isOpaque()) {
+        // If this bitmap is opaque, we don't have any sensible default color,
+        // so we just return uninitialized pixels.
         if (!bitmap.tryAllocPixels(info)) {
             return nullptr;
         }
-        if (!bitmap.info().isOpaque()) {
-            bitmap.eraseColor(SK_ColorTRANSPARENT);
+    } else {
+        // This bitmap has transparency, so we'll zero the pixels (to transparent).
+        // We use a ZeroedPRFactory as a faster alloc-then-eraseColor(SK_ColorTRANSPARENT).
+        SkMallocPixelRef::ZeroedPRFactory factory;
+        if (!bitmap.tryAllocPixels(info, &factory, nullptr/*color table*/)) {
+            return nullptr;
         }
     }
 
diff --git a/src/core/SkMallocPixelRef.cpp b/src/core/SkMallocPixelRef.cpp
index 0196e046b1..fffc044848 100644
--- a/src/core/SkMallocPixelRef.cpp
+++ b/src/core/SkMallocPixelRef.cpp
@@ -48,9 +48,10 @@ SkMallocPixelRef* SkMallocPixelRef::NewDirect(const SkImageInfo& info,
 }
 
 
-SkMallocPixelRef* SkMallocPixelRef::NewAllocate(const SkImageInfo& info,
-                                                size_t requestedRowBytes,
-                                                SkColorTable* ctable) {
+ SkMallocPixelRef* SkMallocPixelRef::NewUsing(void*(*alloc)(size_t),
+                                              const SkImageInfo& info,
+                                              size_t requestedRowBytes,
+                                              SkColorTable* ctable) {
     if (!is_valid(info, ctable)) {
         return nullptr;
     }
@@ -78,7 +79,7 @@ SkMallocPixelRef* SkMallocPixelRef::NewAllocate(const SkImageInfo& info,
 
     size_t size = sk_64_asS32(bigSize);
     SkASSERT(size >= info.getSafeSize(rowBytes));
-    void* addr = sk_malloc_flags(size, 0);
+    void* addr = alloc(size);
     if (nullptr == addr) {
         return nullptr;
     }
@@ -86,6 +87,19 @@ SkMallocPixelRef* SkMallocPixelRef::NewAllocate(const SkImageInfo& info,
     return new SkMallocPixelRef(info, addr, rowBytes, ctable, sk_free_releaseproc, nullptr);
 }
 
+SkMallocPixelRef* SkMallocPixelRef::NewAllocate(const SkImageInfo& info,
+                                                size_t rowBytes,
+                                                SkColorTable* ctable) {
+    auto sk_malloc_nothrow = [](size_t size) { return sk_malloc_flags(size, 0); };
+    return NewUsing(sk_malloc_nothrow, info, rowBytes, ctable);
+}
+
+SkMallocPixelRef* SkMallocPixelRef::NewZeroed(const SkImageInfo& info,
+                                              size_t rowBytes,
+                                              SkColorTable* ctable) {
+    return NewUsing(sk_calloc, info, rowBytes, ctable);
+}
+
 SkMallocPixelRef* SkMallocPixelRef::NewWithProc(const SkImageInfo& info,
                                                 size_t rowBytes,
                                                 SkColorTable* ctable,
@@ -201,3 +215,8 @@ SkPixelRef* SkMallocPixelRef::PRFactory::create(const SkImageInfo& info, size_t
                                                 SkColorTable* ctable) {
     return SkMallocPixelRef::NewAllocate(info, rowBytes, ctable);
 }
+
+SkPixelRef* SkMallocPixelRef::ZeroedPRFactory::create(const SkImageInfo& info, size_t rowBytes,
+                                                      SkColorTable* ctable) {
+    return SkMallocPixelRef::NewZeroed(info, rowBytes, ctable);
+}