SmartClip: Remove unused member variable

Recent Clang versions (r317076+) warn about this.

Bug: 780523
Change-Id: I6e608b49ef3bd8579165cf831f6b44c67bea3f2a
Reviewed-on: https://chromium-review.googlesource.com/749685Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513302}

third_party/WebKit/Source/core/frame/SmartClip.cpp

@@ -100,7 +100,6 @@ SmartClipData SmartClip::DataForRect(const IntRect& crop_rect_in_viewport) {
   }
 
   return SmartClipData(
-      best_node,
       frame_->GetDocument()->View()->ContentsToViewport(united_rects),
       collected_text.ToString());
 }

third_party/WebKit/Source/core/frame/SmartClip.h

@@ -42,16 +42,15 @@ class CORE_EXPORT SmartClipData {
   STACK_ALLOCATED();
 
  public:
-  SmartClipData() : is_empty_(true) {}
+  SmartClipData() {}
 
-  SmartClipData(Node* node, IntRect rect, String string)
-      : is_empty_(!node), rect_in_viewport_(rect), string_(string) {}
+  SmartClipData(IntRect rect, String string)
+      : rect_in_viewport_(rect), string_(string) {}
 
   IntRect RectInViewport() const;
   const String& ClipData() const;
 
  private:
-  bool is_empty_;
   IntRect rect_in_viewport_;
   String string_;
 };