Introduce Editor::Command::CanExecute().

This CL introduces Editor::Command::CanExecute(), and move the predicate
in Editor::Command::Execute() to it, make Editor::Command::Execute()
simple and improve code health.
Signed-off-by: Zhuoyu Qian <zhuoyu.qian@samsung.com>
Change-Id: Iae25f9ebd4d7554e83a9a819c562fae85c2dedc6
Reviewed-on: https://chromium-review.googlesource.com/954773Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543999}

third_party/WebKit/Source/core/editing/Editor.h

@@ -112,6 +112,7 @@ class CORE_EXPORT Editor final : public GarbageCollectedFinalized<Editor> {
                  Event* triggering_event = nullptr) const;
     bool Execute(Event* triggering_event) const;
 
+    bool CanExecute(Event* triggering_event = nullptr) const;
     bool IsSupported() const;
     bool IsEnabled(Event* triggering_event = nullptr) const;
 

third_party/WebKit/Source/core/editing/commands/EditorCommand.cpp

@@ -260,7 +260,7 @@ class EditorInternalCommand {
   EditingTriState (*state)(LocalFrame&, Event*);
   String (*value)(const EditorInternalCommand&, LocalFrame&, Event*);
   bool is_text_insertion;
-  bool (*canExecute)(LocalFrame&, EditorCommandSource);
+  bool (*can_execute)(LocalFrame&, EditorCommandSource);
 };
 
 static const bool kNotTextInsertion = false;
@@ -3554,16 +3554,8 @@ Editor::Command::Command(const EditorInternalCommand* command,
 
 bool Editor::Command::Execute(const String& parameter,
                               Event* triggering_event) const {
-  // TODO(yosin) We should move this logic into |canExecute()| member function
-  // in |EditorInternalCommand| to replace |allowExecutionWhenDisabled|.
-  // |allowExecutionWhenDisabled| is for "Copy", "Cut" and "Paste" commands
-  // only.
-  if (!IsEnabled(triggering_event)) {
-    // Let certain commands be executed when performed explicitly even if they
-    // are disabled.
-    if (!IsSupported() || !frame_ || !command_->canExecute(*frame_, source_))
-      return false;
-  }
+  if (!CanExecute(triggering_event))
+    return false;
 
   if (source_ == EditorCommandSource::kMenuOrKeyBinding) {
     InputEvent::InputType input_type =
@@ -3590,6 +3582,12 @@ bool Editor::Command::Execute(Event* triggering_event) const {
   return Execute(String(), triggering_event);
 }
 
+bool Editor::Command::CanExecute(Event* triggering_event) const {
+  if (IsEnabled(triggering_event))
+    return true;
+  return IsSupported() && frame_ && command_->can_execute(*frame_, source_);
+}
+
 bool Editor::Command::IsSupported() const {
   if (!command_)
     return false;