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/src/gpu/vk/GrVkDescriptorPool.h b/src/gpu/vk/GrVkDescriptorPool.h
index 5327a7d..97c27e1 100644
--- a/src/gpu/vk/GrVkDescriptorPool.h
+++ b/src/gpu/vk/GrVkDescriptorPool.h
@@ -33,7 +33,7 @@
 
 #ifdef SK_TRACE_VK_RESOURCES
     void dumpInfo() const override {
-        SkDebugf("GrVkDescriptorPool: %d, type %d (%d refs)\n", fDescPool, fType, 
+        SkDebugf("GrVkDescriptorPool: %d, type %d (%d refs)\n", fDescPool, fType,
                  this->getRefCnt());
     }
 #endif