Linux: move X operations from the IO to UI2 thread.

Currently we perform several X operations on the IO thread including
geometry and clipboard work. This is causing races inside Xlib and
crashing the browser.

These are the result of synchronous calls from the renderer, so we
cannot route these requests to the UI thread without risking deadlock.
Thus we introduce the UI2 thread. This thread has a second connection
to the X server and can perform X operations safely the without UI
thread.

Work remains to be done:

Since we still have the hack where we pass GtkWidget pointers into the
renderer and back, we still have to access these structures from the
IO and UI2 threads. This still needs to be fixed, but this is not the
patch for it.

Also, not all the X calls from the IO thread have been moved over in
this patch; just a few small ones.

http://codereview.chromium.org/67145


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@14075 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 0 deletions

diff --git a/chrome/browser/chrome_thread.h b/chrome/browser/chrome_thread.h
index 6570f92..1fd1901 100644
--- a/chrome/browser/chrome_thread.h
+++ b/chrome/browser/chrome_thread.h
@@ -38,6 +38,16 @@ class ChromeThread : public base::Thread {
     // This is the thread that interacts with the database.
     DB,
 
+    // This is the thread that interacts with the history database.
+    HISTORY,
+
+#if defined(OS_LINUX)
+    // This thread has a second connection to the X server and is used to
+    // process UI requests when routing the request to the UI thread would risk
+    // deadlock.
+    BACKGROUND_X11,
+#endif
+
     // This identifier does not represent a thread.  Instead it counts the
     // number of well-known threads.  Insert new well-known threads before this
     // identifier.