commit dc3c38b3d7a174fe2e4c8ac38cbd33a1f6a224cc
author Xianzhu Wang <wangxianzhu@chromium.org> Sun Aug 23 00:01:35 2020
committer Xianzhu Wang <wangxianzhu@chromium.org> Sun Aug 23 00:01:35 2020
tree bc8d8d66dfaea21ceac0e337aa231698343f9831
parent 9d5a755bb3fe373a83cb8d70952136de8500bee2

Don't enter "full screen within tab" if there is no visible capturer

"Full screen within tab" [1] is to let an element requesting full
screen to fill the tab space instead of the screen space. It allows the
user to operate the tab (e.g. switching to another tab, dragging the
tab) using the non-full-screen browser UI when capturing a screenshot or
video of the full screen rendering of a web page. These capturers are
operated by the user to capture a visible tab. They start capturing by
calling WebContents::IncrementCaptureCount(size, /*stay_hidden*/false).
These capturers are called "visible capturer" in WebContents.

Internal capturers capture tab rendering (either visible or invisible)
for internal use (e.g. to generate a tab thumbnail), without user
awareness, so they should never have side-effects, thus should never
cause full screen to enter the "within tab" mode. These captures
start capturing by calling
WebContents::IncrementCaptureCount(size, /*stay_hidden*/true).
These capturers are called "hidden capturer" in WebContents.

This CL prevents the tab from entering the "full screen within tab"
mode when there is no visible capturer.

[1] https://source.chromium.org/chromium/chromium/src/+/master:chrome/browser/ui/exclusive_access/fullscreen_within_tab_helper.h;drc=4f51d5d775713e1b428ad8fa5ee131c411753f3c;l=15

TBR=wangxianzhu@chromium.org

(cherry picked from commit c61434c25802f28ae60b401daad0766e35ca669e)

Bug: 1112607
Change-Id: I1b910eeb68077f02be00c56c86f9a5bf0f0bcfc2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2365226
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#800678}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2370660
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/branch-heads/4183@{#1657}
Cr-Branched-From: 740e9e8a40505392ba5c8e022a8024b3d018ca65-refs/heads/master@{#782793}