Linux: server side backing stores

Linux: server side backing stores

This converts Linux to using server-side backing stores. Rather than
keeping a backing store in heap memory in the browser, we create a
pixmap in the X server. This means that expose messages don't require
us to transport any images to the X server, we can just direct it to
paint from the pixmap. Also, scrolling can be performed server side
also. This greatly improves performance over remote X.

Also, shared memory transport to the X server is implemented. Shared
memory segments can be created in the renderer and mapped directly
into the X server.

[Evan Martin, 2009-02-25 19:42:28]

I also think you should check in your xcb stuff (maybe with a comment at the top
saying "this isn't used yet") just so it isn't lost.

http://codereview.chromium.org/27147/diff/1/4
File chrome/browser/renderer_host/backing_store.cc (right):

http://codereview.chromium.org/27147/diff/1/4#newcode9
Line 9: class RenderWidgetHost;
no longer needed if you include above

http://codereview.chromium.org/27147/diff/1/8
File chrome/browser/renderer_host/backing_store_x.cc (right):

http://codereview.chromium.org/27147/diff/1/8#newcode54
Line 54: if (!display_)
this only occurs in unit tests, right?

http://codereview.chromium.org/27147/diff/1/20
File chrome/browser/renderer_host/test_render_view_host.cc (right):

http://codereview.chromium.org/27147/diff/1/20#newcode6
Line 6: #include "chrome/browser/renderer_host/test_render_view_host.h"
this header should be first (stick anohter newline after it to make it clear)

http://codereview.chromium.org/27147/diff/1/20#newcode66
Line 66: BackingStore* TestRenderWidgetHostView::AllocBackingStore(const
gfx::Size& size) {
80

http://codereview.chromium.org/27147/diff/1/25
File chrome/common/x11_util.cc (right):

http://codereview.chromium.org/27147/diff/1/25#newcode114
Line 114: return pictformat;
you return here, but hten have more code later... ?

http://codereview.chromium.org/27147/diff/1/25#newcode150
Line 150: NOTREACHED();
Can you stick a comment in here that we've already probed the server and had an
XShmAttach succeed in the past?

[agl, 2009-02-25 19:56:15]

http://codereview.chromium.org/27147/diff/1/4
File chrome/browser/renderer_host/backing_store.cc (right):

http://codereview.chromium.org/27147/diff/1/4#newcode9
Line 9: class RenderWidgetHost;
On 2009/02/25 19:42:28, Evan Martin wrote:
> no longer needed if you include above

Done.

http://codereview.chromium.org/27147/diff/1/8
File chrome/browser/renderer_host/backing_store_x.cc (right):

http://codereview.chromium.org/27147/diff/1/8#newcode54
Line 54: if (!display_)
On 2009/02/25 19:42:28, Evan Martin wrote:
> this only occurs in unit tests, right?

Right. Comment added.

http://codereview.chromium.org/27147/diff/1/20
File chrome/browser/renderer_host/test_render_view_host.cc (right):

http://codereview.chromium.org/27147/diff/1/20#newcode6
Line 6: #include "chrome/browser/renderer_host/test_render_view_host.h"
On 2009/02/25 19:42:28, Evan Martin wrote:
> this header should be first (stick anohter newline after it to make it clear)

Done.

http://codereview.chromium.org/27147/diff/1/20#newcode66
Line 66: BackingStore* TestRenderWidgetHostView::AllocBackingStore(const
gfx::Size& size) {
On 2009/02/25 19:42:28, Evan Martin wrote:
> 80

Done.

http://codereview.chromium.org/27147/diff/1/25
File chrome/common/x11_util.cc (right):

http://codereview.chromium.org/27147/diff/1/25#newcode114
Line 114: return pictformat;
On 2009/02/25 19:42:28, Evan Martin wrote:
> you return here, but hten have more code later... ?

Good point. That was debugging code. Removed.

http://codereview.chromium.org/27147/diff/1/25#newcode150
Line 150: NOTREACHED();
On 2009/02/25 19:42:28, Evan Martin wrote:
> Can you stick a comment in here that we've already probed the server and had
an
> XShmAttach succeed in the past?

Done.