Remove ContextClient from NavigatorDoNotTrack

Now that Navigator's suppelemnt can access the Navigator object via host(),
it doesn't need to observe ContextClient.

BUG=610176

Review-Url: https://codereview.chromium.org/2615153002
Cr-Commit-Position: refs/heads/master@{#441890}

third_party/WebKit/Source/modules/donottrack/NavigatorDoNotTrack.cpp

@@ -36,12 +36,11 @@
 
 namespace blink {
 
-NavigatorDoNotTrack::NavigatorDoNotTrack(LocalFrame* frame)
-    : ContextClient(frame) {}
+NavigatorDoNotTrack::NavigatorDoNotTrack(Navigator& navigator)
+    : Supplement<Navigator>(navigator) {}
 
 DEFINE_TRACE(NavigatorDoNotTrack) {
   Supplement<Navigator>::trace(visitor);
-  ContextClient::trace(visitor);
 }
 
 const char* NavigatorDoNotTrack::supplementName() {
@@ -52,7 +51,7 @@ NavigatorDoNotTrack& NavigatorDoNotTrack::from(Navigator& navigator) {
   NavigatorDoNotTrack* supplement = static_cast<NavigatorDoNotTrack*>(
       Supplement<Navigator>::from(navigator, supplementName()));
   if (!supplement) {
-    supplement = new NavigatorDoNotTrack(navigator.frame());
+    supplement = new NavigatorDoNotTrack(navigator);
     provideTo(navigator, supplementName(), supplement);
   }
   return *supplement;
@@ -63,9 +62,10 @@ String NavigatorDoNotTrack::doNotTrack(Navigator& navigator) {
 }
 
 String NavigatorDoNotTrack::doNotTrack() {
-  if (!frame() || !frame()->loader().client())
+  LocalFrame* frame = host()->frame();
+  if (!frame || !frame->loader().client())
     return String();
-  return frame()->loader().client()->doNotTrackValue();
+  return frame->loader().client()->doNotTrackValue();
 }
 
 }  // namespace blink

third_party/WebKit/Source/modules/donottrack/NavigatorDoNotTrack.h

@@ -31,7 +31,6 @@
 #ifndef NavigatorDoNotTrack_h
 #define NavigatorDoNotTrack_h
 
-#include "core/dom/ContextLifecycleObserver.h"
 #include "core/frame/Navigator.h"
 #include "platform/Supplementable.h"
 #include "platform/heap/Handle.h"
@@ -39,12 +38,10 @@
 
 namespace blink {
 
-class LocalFrame;
 class Navigator;
 
 class NavigatorDoNotTrack final : public GarbageCollected<NavigatorDoNotTrack>,
-                                  public Supplement<Navigator>,
-                                  public ContextClient {
+                                  public Supplement<Navigator> {
   USING_GARBAGE_COLLECTED_MIXIN(NavigatorDoNotTrack);
 
  public:
@@ -56,7 +53,7 @@ class NavigatorDoNotTrack final : public GarbageCollected<NavigatorDoNotTrack>,
   DECLARE_VIRTUAL_TRACE();
 
  private:
-  explicit NavigatorDoNotTrack(LocalFrame*);
+  explicit NavigatorDoNotTrack(Navigator&);
   static const char* supplementName();
 };