add new readPixels with direct memory parameters

src/gpu/SkGpuDevice.cpp

Index: src/gpu/SkGpuDevice.cpp
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index a86170b75e1aa88bba07f670fa4ba87b31a4048a..59b659656f66d9b3233005618ea00fa61580e4d8 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -372,6 +372,29 @@ GrPixelConfig config8888_to_grconfig_and_flags(SkCanvas::Config8888 config8888,
 }
 }
 
+#ifdef SK_SUPPORT_LEGACY_WRITEPIXELSCONFIG
+void SkGpuDevice::writePixels(const SkBitmap& bitmap, int x, int y,
+                              SkCanvas::Config8888 config8888) {
+    SkAutoLockPixels alp(bitmap);
+    if (!bitmap.readyToDraw()) {
+        return;
+    }
+
+    GrPixelConfig config;
+    uint32_t flags;
+    if (SkBitmap::kARGB_8888_Config == bitmap.config()) {
+        config = config8888_to_grconfig_and_flags(config8888, &flags);
+    } else {
+        flags = 0;
+        config= SkBitmapConfig2GrPixelConfig(bitmap.config());
+    }
+
+    fRenderTarget->writePixels(x, y, bitmap.width(), bitmap.height(),
+                               config, bitmap.getPixels(), bitmap.rowBytes(), flags);
+}
+#endif
+
+#ifdef SK_SUPPORT_LEGACY_READPIXELSCONFIG
 bool SkGpuDevice::onReadPixels(const SkBitmap& bitmap,
                                int x, int y,
                                SkCanvas::Config8888 config8888) {
@@ -379,7 +402,7 @@ bool SkGpuDevice::onReadPixels(const SkBitmap& bitmap,
     SkASSERT(SkBitmap::kARGB_8888_Config == bitmap.config());
     SkASSERT(!bitmap.isNull());
     SkASSERT(SkIRect::MakeWH(this->width(), this->height()).contains(SkIRect::MakeXYWH(x, y, bitmap.width(), bitmap.height())));
-
+    
     SkAutoLockPixels alp(bitmap);
     GrPixelConfig config;
     uint32_t flags;
@@ -393,28 +416,25 @@ bool SkGpuDevice::onReadPixels(const SkBitmap& bitmap,
                                             bitmap.rowBytes(),
                                             flags);
 }
+#endif
 
-#ifdef SK_SUPPORT_LEGACY_WRITEPIXELSCONFIG
-void SkGpuDevice::writePixels(const SkBitmap& bitmap, int x, int y,
-                              SkCanvas::Config8888 config8888) {
-    SkAutoLockPixels alp(bitmap);
-    if (!bitmap.readyToDraw()) {
-        return;
-    }
+bool SkGpuDevice::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
+                               int x, int y) {
+    DO_DEFERRED_CLEAR();
 
-    GrPixelConfig config;
-    uint32_t flags;
-    if (SkBitmap::kARGB_8888_Config == bitmap.config()) {
-        config = config8888_to_grconfig_and_flags(config8888, &flags);
-    } else {
-        flags = 0;
-        config= SkBitmapConfig2GrPixelConfig(bitmap.config());
+    // TODO: teach fRenderTarget to take ImageInfo directly to specify the src pixels
+    GrPixelConfig config = SkImageInfo2GrPixelConfig(dstInfo.colorType(), dstInfo.alphaType());
+    if (kUnknown_GrPixelConfig == config) {
+        return false;
     }
 
-    fRenderTarget->writePixels(x, y, bitmap.width(), bitmap.height(),
-                               config, bitmap.getPixels(), bitmap.rowBytes(), flags);
+    uint32_t flags = 0;
+    if (kUnpremul_SkAlphaType == dstInfo.alphaType()) {
+        flags = GrContext::kUnpremul_PixelOpsFlag;
+    }
+    return fContext->readRenderTargetPixels(fRenderTarget, x, y, dstInfo.width(), dstInfo.height(),
+                                            config, dstPixels, dstRowBytes, flags);
 }
-#endif
 
 bool SkGpuDevice::onWritePixels(const SkImageInfo& info, const void* pixels, size_t rowBytes,
                                 int x, int y) {