change clip-bounds getters to always return the rect
(actually fixes undefined result in getClipBounds)

future CLs
- update all callers to new apis
- move/rename virtuals

BUG=skia:

DOCS_PREVIEW= https://skia.org/?cl=7400

Change-Id: I45b93014e915c0d1c36d97d948c9ac8931f23258
Reviewed-on: https://skia-review.googlesource.com/7400
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/bench/SKPBench.cpp b/bench/SKPBench.cpp
index 9d4dcc5..013ec53 100644
--- a/bench/SKPBench.cpp
+++ b/bench/SKPBench.cpp
@@ -50,8 +50,8 @@
 }
 
 void SKPBench::onPerCanvasPreDraw(SkCanvas* canvas) {
-    SkIRect bounds;
-    SkAssertResult(canvas->getClipDeviceBounds(&bounds));
+    SkIRect bounds = canvas->getDeviceClipBounds();
+    SkAssertResult(!bounds.isEmpty());
 
     const bool gpu = canvas->getGrContext() != nullptr;
     int tileW = gpu ? FLAGS_GPUbenchTileW : FLAGS_CPUbenchTileW,