[iOS] Convert FullscreenController to a Data.

This will allow it to be accessible to multiple parts of the UI via
a shared ChromeBrowserState.

Bug: 785663
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ia371a98681d27522443fbc0726fa4932e7666ae1
Reviewed-on: https://chromium-review.googlesource.com/802829
Commit-Queue: Kurt Horimoto <kkhorimoto@chromium.org>
Reviewed-by: Kurt Horimoto <kkhorimoto@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521084}

ios/chrome/browser/ui/fullscreen/fullscreen_controller.h

@@ -9,6 +9,7 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "base/supports_user_data.h"
 
 @class ChromeBroadcaster;
 @class ChromeBroadcastOberverBridge;
@@ -20,10 +21,21 @@ class FullscreenWebStateListObserver;
 // calculates how much of the toolbar should be visible as a result.  When the
 // user scrolls down the screen, the toolbar should be hidden to allow more of
 // the page's content to be visible.
-class FullscreenController {
+class FullscreenController : public base::SupportsUserData::Data {
  public:
-  explicit FullscreenController(ChromeBroadcaster* broadcaster);
-  ~FullscreenController();
+  ~FullscreenController() override;
+
+  // Creation and getter functions for FullscreenController.
+  // TODO(crbug.com/790886): Convert FullscreenController to a BrowserUserData.
+  static void CreateForUserData(base::SupportsUserData* user_data);
+  static FullscreenController* FromUserData(base::SupportsUserData* user_data);
+
+  // The ChromeBroadcaster through the FullscreenController receives UI
+  // information necessary to calculate fullscreen progress.
+  // TODO(crbug.com/790886): Once FullscreenController is a BrowserUserData,
+  // remove this ad-hoc broadcaster and drive the animations via the Browser's
+  // ChromeBroadcaster.
+  ChromeBroadcaster* broadcaster() { return broadcaster_; }
 
   // Adds and removes FullscreenControllerObservers.
   void AddObserver(FullscreenControllerObserver* observer);
@@ -42,6 +54,9 @@ class FullscreenController {
   void DecrementDisabledCounter();
 
  private:
+  // Private contructor used by CreateForUserData().
+  explicit FullscreenController();
+
   // The broadcaster that drives the model.
   __strong ChromeBroadcaster* broadcaster_ = nil;
   // The model used to calculate fullscreen state.

ios/chrome/browser/ui/fullscreen/fullscreen_controller.mm

@@ -14,8 +14,31 @@
 #error "This file requires ARC support."
 #endif
 
-FullscreenController::FullscreenController(ChromeBroadcaster* broadcaster)
-    : broadcaster_(broadcaster),
+namespace {
+// The key under which FullscreenControllers are associated with their user
+// data.
+const void* const kFullscreenControllerKey = &kFullscreenControllerKey;
+}  // namespace
+
+// static
+void FullscreenController::CreateForUserData(
+    base::SupportsUserData* user_data) {
+  DCHECK(user_data);
+  if (!FullscreenController::FromUserData(user_data)) {
+    user_data->SetUserData(kFullscreenControllerKey,
+                           base::WrapUnique(new FullscreenController()));
+  }
+}
+
+// static
+FullscreenController* FullscreenController::FromUserData(
+    base::SupportsUserData* user_data) {
+  return static_cast<FullscreenController*>(
+      user_data->GetUserData(kFullscreenControllerKey));
+}
+
+FullscreenController::FullscreenController()
+    : broadcaster_([[ChromeBroadcaster alloc] init]),
       model_(base::MakeUnique<FullscreenModel>()),
       bridge_([[ChromeBroadcastOberverBridge alloc]
           initWithObserver:model_.get()]) {