[Mac] Bounce app shims when app windows request attention.

apps/app_shim/app_shim_messages.h

Index: apps/app_shim/app_shim_messages.h
diff --git a/apps/app_shim/app_shim_messages.h b/apps/app_shim/app_shim_messages.h
index 75be2d0c685f7815ce86d24db5889ce05276afbf..9b8556b7d2100f77c5a1798a727e4a3abd524e84 100644
--- a/apps/app_shim/app_shim_messages.h
+++ b/apps/app_shim/app_shim_messages.h
@@ -21,6 +21,8 @@ IPC_ENUM_TRAITS_MAX_VALUE(apps::AppShimLaunchResult,
                           apps::APP_SHIM_LAUNCH_NUM_RESULTS - 1)
 IPC_ENUM_TRAITS_MAX_VALUE(apps::AppShimFocusType,
                           apps::APP_SHIM_FOCUS_NUM_TYPES - 1)
+IPC_ENUM_TRAITS_MAX_VALUE(apps::AppShimAttentionType,
+                          apps::APP_SHIM_ATTENTION_NUM_TYPES - 1)
 
 // Signals that a previous LaunchApp message has been processed, and lets the
 // app shim process know whether it was registered successfully.
@@ -31,7 +33,8 @@ IPC_MESSAGE_CONTROL1(AppShimMsg_LaunchApp_Done,
 IPC_MESSAGE_CONTROL0(AppShimMsg_Hide)
 
 // Instructs the shim to request user attention.
-IPC_MESSAGE_CONTROL0(AppShimMsg_RequestUserAttention)
+IPC_MESSAGE_CONTROL1(AppShimMsg_RequestUserAttention,

[tapted, 2014/08/13 03:37:08]

So.. now that this is released, I'm not sure how safe it is to change message
sizes.

I think if you:

1. Run Chrome
2. Have un upgrade come in; downloaded waiting for a relaunch
3. Launch an App without relaunching chrome
4. that app does requestUserAttention


Then the IPC messages will get out of sync, and the shim will probably freeze or
behave randomly. Probably bad enough and hidden enough (i.e. we won't get crash
reports) to want to avoid.

Adding a new message type should work, with a TODO to remove the old IPC message
in a few milestones. But it's yucky.

Maybe our lives will be easier if we can trick the app_mode_loader to load the
framework of the chrome it's connecting to, rather than the one that will be
used next time chrome is run - WDYT?

[jackhou1, 2014/08/13 05:53:45]

Argh.

Just adding a new IPC message instead.

As discussed, it's probably not safe to delete any either. I added a comment
about this.

I think it'd be tedious trying to guarantee that the shim and Chrome have the
same framework version. It's easier just to make sure the IPC messages are
consistent. If for some reason we plan to add/change a heap of app shim
messages, we should probably switch to something more robust, like Mojo.

+                     apps::AppShimAttentionType /* attention_type */)
 
 // Signals to the main Chrome process that a shim has started indicating the
 // profile and app_id that the shim should be associated with and whether to