Add viewer mode to VisualBench.

Displays each benchmark/skp with a graph showing a series of frame times.
Use the space bar to skip to the next benchmark.

Adds an option to hit ESC to quit VisualBench. Useful in fullscreen mode.

Review URL: https://codereview.chromium.org/1336043003
diff --git a/tools/VisualBench/VisualLightweightBenchModule.cpp b/tools/VisualBench/VisualLightweightBenchModule.cpp
index 8f9e488..bc592a3 100644
--- a/tools/VisualBench/VisualLightweightBenchModule.cpp
+++ b/tools/VisualBench/VisualLightweightBenchModule.cpp
@@ -127,7 +127,9 @@
         return false;
     }
 
-    canvas->clear(0xffffffff);
+    fOwner->clear(canvas, SK_ColorWHITE, 2);
+
+
     fBenchmark->preDraw();
     fRecords.push_back();
 
@@ -254,3 +256,7 @@
         fCurrentFrame++;
     }
 }
+
+bool VisualLightweightBenchModule::onHandleChar(SkUnichar c) {
+    return true;
+}