Preview CL for adding an Infobar facility to Google Chrome Frame....

chrome_frame/infobars/internal/displaced_window.h

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_FRAME_INFOBARS_INTERNAL_DISPLACED_WINDOW_H_
+#define CHROME_FRAME_INFOBARS_INTERNAL_DISPLACED_WINDOW_H_
+
+#include <atlbase.h>
+#include <atlapp.h>  // Must be included AFTER base.
+#include <atlcrack.h>
+
+#include "base/basictypes.h"
+#include "base/task_queue.h"
+
+// DisplacedWindowManager observes the HWND passed to Initialize and:
+// 1) Intercepts NCCALCSIZE events allowing the client to modify the window's
+//    requested dimensions.
+// 2) Allows the client to request a recalculation of the window's dimensions
+//    (resulting in a deferred callback as in [1]).
+// 3) Notifies the client when the window is destroyed.
+class DisplacedWindowManager : public CWindowImpl<DisplacedWindowManager> {
+ public:
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+    // Receives the natural dimensions of the displaced window. Upon return,
+    // rect should contain the adjusted dimensions (i.e., possibly reduced to
+    // accomodate an infobar).
+    virtual void AdjustDisplacedWindowDimensions(RECT* rect) = 0;
+    // Receives notification that the displaced window is being destroyed.
+    // The DisplacedWindowManager instance may be deleted at any time following
+    // this call.
+    virtual void OnDisplacedWindowDestroyed() = 0;
+  };
+
+  DisplacedWindowManager();
+
+  // Returns true if the provided window may be observed, in which case this
+  // instance will take responsibility for its own destruction when the window
+  // is destroyed. If this method returns false, the caller should delete the
+  // instance immediately.
+  // In either case, takes ownership of delegate, which will be destroyed when
+  // this instance is destroyed.
+  bool Initialize(HWND displaced_hwnd, Delegate* delegate);
+
+  // Triggers a deferred re-evaluation of the dimensions of the displaced
+  // window. Delegate::AdjustDisplacedWindowDimensions will be called with the
+  // natural dimensions of the displaced window.
+  void UpdateLayout();
+
+  BEGIN_MSG_MAP_EX(DisplacedWindowManager)
+    MSG_WM_NCCALCSIZE(OnNcCalcSize)
+    MSG_WM_DESTROY(OnDestroy)
+    MESSAGE_HANDLER(TM_RUN_TASK_QUEUE, OnRunTaskQueue)
+  END_MSG_MAP()
+
+ private:
+  enum DisplacedWindowUserMessages {
+    TM_RUN_TASK_QUEUE = WM_USER + 600,

[tommi (sloooow) - chröme, 2010/11/24 16:08:24]

use WM_APP instead of WM_USER.

[erikwright (departed), 2010/12/01 20:05:52]

Now uses RegisterWindowEvent (see subclassing_window.h).

+  };
+
+  // Schedules a deferred task on the window message loop of this instance's

[erikwright (departed), 2010/11/24 06:24:56]

To verify whether or not this really needs to be deferred. If not (my
suspicion), I'll get rid of the task queue altogether.

[erikwright (departed), 2010/12/01 20:05:52]

Verified that it does not need to be deferred. Yay.

+  // managed window. The task may not occur if the window is destroyed first.
+  void PushTask(Task* task);
+
+  // Respond to a private message we send ourselves in order to trigger
+  // deferred processing of items in the TaskQueue.
+  LRESULT OnRunTaskQueue(UINT message,
+                         WPARAM wparam,
+                         LPARAM lparam,
+                         BOOL& handled);
+
+  void DoUpdateLayout();
+  // The size of the displaced window is being calculated. Allow

[tommi (sloooow) - chröme, 2010/11/24 16:08:24]

add empty lines between functions

[erikwright (departed), 2010/12/01 20:05:52]

Done.

+  // InfobarWindows to reserve a part of the space for themselves, if they are
+  // visible.
+  LRESULT OnNcCalcSize(BOOL calc_valid_rects, LPARAM lparam);
+  // The displaced window has been destroyed. Inform the InfobarManagerImpl,
+  // who will orphan this instance. We will delete ourselves in
+  // OnFinalMessage.
+  void OnDestroy();
+  // This instance is now free to be deleted.
+  void OnFinalMessage(HWND);

[tommi (sloooow) - chröme, 2010/11/24 16:08:24]

virtual?

btw, even though you declare it as private, the function is really public since
the interface it is declared in, declares it as such.

[erikwright (departed), 2010/12/01 20:05:52]

Thanks. Simply a mistake that it was in this section. I didn't know about the
style-guide rule to include 'virtual' when overriding virtual methods.

+
+  scoped_ptr<Delegate> delegate_;
+  TaskQueue task_queue_;
+  DISALLOW_COPY_AND_ASSIGN(DisplacedWindowManager);
+};
+
+#endif  // CHROME_FRAME_INFOBARS_INTERNAL_DISPLACED_WINDOW_H_