Remove trailing whitespace.

Also adds a presubmit to prevent adding trailing whitespace to source
code in the future.

Change-Id: I41a4df81487f6f00aa19b188f0cac6a3377efde6
Reviewed-on: https://skia-review.googlesource.com/57380
Reviewed-by: Ravi Mistry <rmistry@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/debugger/SkDebugger.cpp b/debugger/SkDebugger.cpp
index 197a27f..7716112 100644
--- a/debugger/SkDebugger.cpp
+++ b/debugger/SkDebugger.cpp
@@ -33,7 +33,7 @@
     // We can't just call clone here since we want to removed the "deleted"
     // commands. Playing back will strip those out.
     SkPictureRecorder recorder;
-    SkCanvas* canvas = recorder.beginRecording(this->pictureCull().width(), 
+    SkCanvas* canvas = recorder.beginRecording(this->pictureCull().width(),
                                                this->pictureCull().height());
 
     bool vizMode = fDebugCanvas->getMegaVizMode();