Remove unused Dispose method from InspectTool

This CL removes InspectTool::Dispose method that was never
implemented by any of the tools.

Change-Id: I5c8c3dea03a0b98f6915f31120f66ab8760c3428
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417891Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808241}

third_party/blink/renderer/core/inspector/inspector_overlay_agent.cc

@@ -471,8 +471,6 @@ Response InspectorOverlayAgent::disable() {
   resize_timer_active_ = false;
   frame_overlay_.reset();
   frame_resource_name_ = 0;
-  if (persistent_tool_)
-    persistent_tool_->Dispose();
   persistent_tool_ = nullptr;
   PickTheRightTool();
   SetNeedsUnbufferedInput(false);
@@ -722,8 +720,6 @@ Response InspectorOverlayAgent::highlightNode(
 Response InspectorOverlayAgent::setShowGridOverlays(
     std::unique_ptr<protocol::Array<protocol::Overlay::GridNodeHighlightConfig>>
         grid_node_highlight_configs) {
-  if (persistent_tool_)
-    persistent_tool_->Dispose();
   persistent_tool_ = nullptr;
 
   if (grid_node_highlight_configs->size()) {
@@ -1395,9 +1391,6 @@ void InspectorOverlayAgent::SetInspectTool(InspectTool* inspect_tool) {
   if (!view || !frame)
     return;
 
-  if (inspect_tool_ && inspect_tool_ != persistent_tool_)
-    inspect_tool_->Dispose();
-
   if (inspect_tool && enabled_.Get()) {
     inspect_tool_ = inspect_tool;
     // If the tool supports persistent overlays, the resources of the persistent

third_party/blink/renderer/core/inspector/inspector_overlay_agent.h

@@ -99,7 +99,6 @@ class CORE_EXPORT InspectTool : public GarbageCollected<InspectTool> {
   virtual void Draw(float scale) {}
   virtual void Dispatch(const String& message) {}
   virtual void Trace(Visitor* visitor) const;
-  virtual void Dispose() {}
   virtual bool HideOnHideHighlight();
   virtual bool HideOnMouseMove();