For Desktop tab sharing, activate selected inactive tab

chrome/browser/ui/views/desktop_media_picker_views.cc

Index: chrome/browser/ui/views/desktop_media_picker_views.cc
diff --git a/chrome/browser/ui/views/desktop_media_picker_views.cc b/chrome/browser/ui/views/desktop_media_picker_views.cc
index cfa7b0ffbbe4a85ea0d2552298547c8f7894edab..0b6cf5ae848e3885c6d50822dab178923ff1e96b 100644
--- a/chrome/browser/ui/views/desktop_media_picker_views.cc
+++ b/chrome/browser/ui/views/desktop_media_picker_views.cc
@@ -13,11 +13,14 @@
 #include "build/build_config.h"
 #include "chrome/browser/media/desktop_media_list.h"
 #include "chrome/browser/ui/ash/ash_util.h"
+#include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/constrained_window/constrained_window_views.h"
 #include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "grit/components_strings.h"
 #include "ui/aura/window_tree_host.h"
@@ -514,15 +517,30 @@ bool DesktopMediaPickerDialogView::Accept() {
 
   // Ok button should only be enabled when a source is selected.
   DCHECK(selection);
-
-  DesktopMediaID source;
-  if (selection)
-    source = selection->source_id();
-
+  DesktopMediaID source = selection->source_id();
   source.audio_share = audio_share_checkbox_ &&
                        audio_share_checkbox_->enabled() &&
                        audio_share_checkbox_->checked();
 
+  // If the media source is an inactive tab, activate it.
+  if (source.type == DesktopMediaID::TYPE_WEB_CONTENTS) {
+    content::WebContents* tab = content::WebContents::FromRenderFrameHost(
+        content::RenderFrameHost::FromID(
+            source.web_contents_id.render_process_id,
+            source.web_contents_id.main_render_frame_id));
+    if (tab) {
+      Browser* browser = chrome::FindBrowserWithWebContents(tab);
+      if (browser) {

[msw, 2016/03/15 23:58:19]

When would browser be null? Do we need to check this?

[GeorgeZ, 2016/03/16 00:32:32]

You are right, as long as tab is valid, browser should be valid.

+        TabStripModel* tab_strip_model = browser->tab_strip_model();
+        DCHECK(tab_strip_model);

[msw, 2016/03/15 23:58:19]

nit: dcheck before dereference is unnecessary.

[GeorgeZ, 2016/03/16 00:32:32]

Done.

+
+        const int tab_index = tab_strip_model->GetIndexOfWebContents(tab);
+        if (tab_index != tab_strip_model->active_index())

[msw, 2016/03/15 23:58:19]

Must we check if the tab is inactive? Otherwise, this whole block becomes:
  tab->GetDelegate()->ActivateContents(tab);
If necessary, use 'tab != browser->tab_strip_model()->GetActiveWebContents()'

[GeorgeZ, 2016/03/16 00:32:32]

A check probably is not necessary.

+          tab->GetDelegate()->ActivateContents(tab);
+      }
+    }
+  }
+
   if (parent_)
     parent_->NotifyDialogResult(source);