Implementation of dwrite font proxy and removal of dwrite font cache

content/common/dwrite_font_proxy_init_win.h

Index: content/common/dwrite_font_proxy_init_win.h
diff --git a/content/common/dwrite_font_proxy_init_win.h b/content/common/dwrite_font_proxy_init_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..a3715d1ba8c71277fa6546a39820597f6ad0deb8
--- /dev/null
+++ b/content/common/dwrite_font_proxy_init_win.h
@@ -0,0 +1,30 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_COMMON_DWRITE_FONT_PROXY_INIT_WIN_H_
+#define CONTENT_COMMON_DWRITE_FONT_PROXY_INIT_WIN_H_
+
+#include "base/callback.h"
+#include "content/common/content_export.h"
+#include "ipc/ipc_sender.h"
+
+namespace content {
+
+typedef IPC::Sender* (*GetSenderFn)();

[jam, 2015/11/03 00:18:54]

we normally don't use function pointers, but instead use closures.

[Ilya Kulshin, 2015/11/03 18:56:22]

Oops, forgot to remove the typedef.

+
+// Initializes the dwrite font proxy.
+void CONTENT_EXPORT
+InitializeDWriteFontProxy(const base::Callback<IPC::Sender*(void)>& sender);

[jam, 2015/11/03 00:18:54]

document what the parameters are.

looking at this, I'm wondering why this is in content/common and it's using an
IPC::Sender? that is normally used for sending IPCs. i.e. it should be in
content/child, since content/common is code that is shared with content/browser
and content/[child processes]

[Ilya Kulshin, 2015/11/03 18:56:21]

Done.

+
+// Uninitialize the dwrite font proxy. This is safe to call even if the proxy
+// has not been initialized. After this, calls to load fonts may fail.
+void CONTENT_EXPORT UninitializeDWriteFontProxy();

[jam, 2015/11/03 00:18:54]

why is this needed?

[Ilya Kulshin, 2015/11/03 18:56:21]

Direct write requires that font collection and font file loaders be registered
prior to use, and subsequently unregistered. We also don't have a good signal
for when the proxy is no longer needed, other than platform uninitialize, which
is where this is called (refcounting wouldn't work, because direct write itself
holds a reference on the loaders). Given that the proxy lives for the life of
the process, it's probably fine to not unregister, but I'd rather unregister
when we have the opportunity to do so.

[jam, 2015/11/09 16:32:08]

i don't see the point of unregistering this before process shut down.

+
+// Configures the dwrite font proxy to use the specified sender. This can be
+// useful in tests which use a fake render thread which is unable to process
+// font IPC messages. This should only be called when running as a test.
+void CONTENT_EXPORT SetDWriteFontProxyTestModeSender(IPC::Sender* sender);
+}  // namespace content
+
+#endif  // CONTENT_COMMON_DWRITE_FONT_PROXY_INIT_WIN_H_