Revert "Delete getRenderTargetHandle call on SkSurface."

This reverts commit c828109ebd1519134b1c3fa168519ac07a31fe05.

Reason for revert: Need to fix flutter

Original change's description:
> Delete getRenderTargetHandle call on SkSurface.
> 
> All clients and internal code should be switched (once changes land soon)
> to the new getBackendRenderTarget call instead.
> 
> Bug: skia:
> Change-Id: I6f490b6d26a72f37f97216be04e541483206510d
> Reviewed-on: https://skia-review.googlesource.com/121103
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,robertphillips@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: skia:
Change-Id: I571298f839757fcdedcd8117519e740ac7ef1344
Reviewed-on: https://skia-review.googlesource.com/121480
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>

1 files changed, 53 insertions, 2 deletions

diff --git a/docs/SkSurface_Reference.bmh b/docs/SkSurface_Reference.bmh
index d3fb13529f..e9c520106b 100644
--- a/docs/SkSurface_Reference.bmh
+++ b/docs/SkSurface_Reference.bmh
@@ -989,7 +989,7 @@ Caller must overwrite the entire back-end object.
     canvas->drawString(str, 20, y += 20, paint);
 ##
 
-#SeeAlso getTextureHandle
+#SeeAlso getTextureHandle getRenderTargetHandle
 
 #Enum ##
 
@@ -1032,7 +1032,58 @@ or when Surface is deleted.
     }
 ##
 
-#SeeAlso GrBackendObject BackendHandleAccess
+#SeeAlso getRenderTargetHandle GrBackendObject BackendHandleAccess
+
+#Method ##
+
+# ------------------------------------------------------------------------------
+
+#Method bool getRenderTargetHandle(GrBackendObject* backendObject,
+                               BackendHandleAccess backendHandleAccess)
+#In Property
+#Line # returns the GPU reference to render target ##
+
+Returns true and stores the GPU back-end reference of the render target used
+by Surface in backendObject.
+
+Return false if Surface is not backed by a GPU render target, and leaves
+backendObject unchanged.
+
+The returned render target handle is only valid until the next draw into Surface,
+or when Surface is deleted.
+
+In OpenGL this returns the frame buffer object ID.
+
+#Param backendObject  GPU intermediate memory buffer ##
+#Param backendHandleAccess  one of:  kFlushRead_BackendHandleAccess,
+        kFlushWrite_BackendHandleAccess, kDiscardWrite_BackendHandleAccess
+##
+
+#Return true if Surface is backed by GPU texture ##
+
+#Example
+#Platform gpu
+#Height 64
+    SkPaint paint;
+    paint.setTextSize(32);
+    GrContext* context = canvas->getGrContext();
+    if (!context) {
+         canvas->drawString("GPU only!", 20, 40, paint);
+         return;
+    }
+    sk_sp<SkSurface> gpuSurface = SkSurface::MakeRenderTarget(
+            context, SkBudgeted::kYes, SkImageInfo::MakeN32Premul(10, 10));
+    GrBackendObject backendObject;
+    if (gpuSurface->getRenderTargetHandle(&backendObject, 
+            SkSurface::kFlushRead_BackendHandleAccess)) {
+        SkString str;
+        str.printf("backendObject=%ld", backendObject);
+        paint.setTextSize(16);
+        canvas->drawString(str, 20, 40, paint);
+    }
+##
+
+#SeeAlso getTextureHandle GrBackendObject BackendHandleAccess
 
 #Method ##