[Reland #1] Remove makeKeyAndOrderFront: from WebContentsViewMac::Focus().

The original CL caused a test failure in
DetachToBrowserTabDragControllerTest.DetachToOwnWindow. This was due to a bug in
the test itself, which was generating an incorrect mouse-up event. This CL fixes
the test to delay generation of the mouse-up event until the new tab dragging
window has been detached.

> WebContentsView::Focus() is supposed to update the first responder of the
> Window, not make the window focused. The latter should go through
> WebContentsDelegate::ActivateContents().
>
> This logic is usually a no-op because the window receiving the call is the
> active window. But in the case where the user quickly switches windows, this can
> cause the old window to re-take focus.
>
> This logic was added in 2009 not because it had the right semantics, but to
> match the behavior of Windows: http://codereview.chromium.org/165492.
>
> Bug: 859614
> Change-Id: I2bc44a825d93159d774c632da17cc2f2d151fc3a
> Reviewed-on: https://chromium-review.googlesource.com/1124772
> Reviewed-by: Avi Drissman <avi@chromium.org>
> Commit-Queue: Erik Chen <erikchen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#573344}

Bug: 859614
Change-Id: I441a00ad015eb3559718b448fc42f98827beee35
Reviewed-on: https://chromium-review.googlesource.com/1132106Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574159}

chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc

@@ -531,6 +531,24 @@ class DetachToBrowserTabDragControllerTest
     return true;
   }
 
+  void ReleaseMouseAfterWindowDetached() {
+    // On macOS, we want to avoid generating the input event [which requires an
+    // associated window] until the window has been detached. Failure to do so
+    // causes odd behavior [e.g. on macOS 10.10, the mouse-up will reactivate
+    // the first window].
+    if (browser_list->size() != 2u) {
+      base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+          FROM_HERE,
+          base::BindOnce(&DetachToBrowserTabDragControllerTest::
+                             ReleaseMouseAfterWindowDetached,
+                         base::Unretained(this)),
+          base::TimeDelta::FromMilliseconds(1));
+      return;
+    }
+
+    ASSERT_TRUE(ReleaseMouseAsync());
+  }
+
   bool ReleaseMouseAsync() {
     return input_source() == INPUT_SOURCE_MOUSE &&
         ui_controls::SendMouseEvents(ui_controls::LEFT, ui_controls::UP);
@@ -934,7 +952,7 @@ IN_PROC_BROWSER_TEST_P(DetachToBrowserTabDragControllerTest,
                   tab_0_center.x(), tab_0_center.y() + GetDetachY(tab_strip),
                   base::Bind(&DetachToOwnWindowStep2, this)));
   if (input_source() == INPUT_SOURCE_MOUSE) {
-    ASSERT_TRUE(ReleaseMouseAsync());
+    ReleaseMouseAfterWindowDetached();
     QuitWhenNotDragging();
   }
 
@@ -1008,7 +1026,7 @@ IN_PROC_BROWSER_TEST_P(DetachToBrowserTabDragControllerTest,
       tab_0_center.x(), tab_0_center.y() + GetDetachY(tab_strip),
       base::Bind(&DetachToOwnWindowStep2, this)));
   if (input_source() == INPUT_SOURCE_MOUSE) {
-    ASSERT_TRUE(ReleaseMouseAsync());
+    ReleaseMouseAfterWindowDetached();
     QuitWhenNotDragging();
   }
 
@@ -1077,7 +1095,7 @@ IN_PROC_BROWSER_TEST_P(DetachToBrowserTabDragControllerTest,
                   tab_0_center.x(), tab_0_center.y() + GetDetachY(tab_strip),
                   base::Bind(&DetachToOwnWindowStep2, this)));
   if (input_source() == INPUT_SOURCE_MOUSE) {
-    ASSERT_TRUE(ReleaseMouseAsync());
+    ReleaseMouseAfterWindowDetached();
     QuitWhenNotDragging();
   }
 
@@ -1134,7 +1152,7 @@ IN_PROC_BROWSER_TEST_P(DetachToBrowserTabDragControllerTest,
       tab_0_center.x(), tab_0_center.y() + GetDetachY(tab_strip),
       base::Bind(&DetachToOwnWindowStep2, this)));
   if (input_source() == INPUT_SOURCE_MOUSE) {
-    ASSERT_TRUE(ReleaseMouseAsync());
+    ReleaseMouseAfterWindowDetached();
     QuitWhenNotDragging();
   }
 

content/browser/web_contents/web_contents_view_mac.mm

@@ -198,9 +198,6 @@ void WebContentsViewMac::Focus() {
   gfx::NativeView native_view = GetNativeViewForFocus();
   NSWindow* window = [native_view window];
   [window makeFirstResponder:native_view];
-  if (![window isVisible])
-    return;
-  [window makeKeyAndOrderFront:nil];
 }
 
 void WebContentsViewMac::SetInitialFocus() {