Linux: Add support for chrooted renderers.

http://code.google.com/p/chromium/wiki/LinuxSandboxIPC

Without filesystem access from the renderers, we need another way of
dealing with fontconfig and font loading.

This add support for:
  * An "SBX_D" environment variable in the renderers which is used to
    signal the end of dynamic linking so that the chroot can be
    enforced.
  * A sandbox_host process, running outside the sandbox, to deal with
    fontconfig requests from the renderers. See the wiki page for
    the reasoning behind making it a separate process.
  * A new, custom SkFontHost for Skia. Because this is Chrome
    specific, it will live outside the upstream Skia tree. This
    FontHost can be configured either to drive fontconfig directly
    (for the browser process and for any unsandboxed renderers) or to
    use an IPC system. Since the same SkFontHost has to be linked into
    both the browser and renderer (they are the same binary), this
    switch has to be made at run time.

Sandbox IPC calls are rare (a couple of dozen at page load time) and
add about 50us of overhead for each call.

(Reland of r17575 which was reverted in r17577)

http://codereview.chromium.org/112074
BUG=8081


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18405 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 60 insertions, 0 deletions

diff --git a/skia/ext/SkFontHost_fontconfig_impl.h b/skia/ext/SkFontHost_fontconfig_impl.h
new file mode 100644
index 0000000..a593891
--- /dev/null
+++ b/skia/ext/SkFontHost_fontconfig_impl.h
@@ -0,0 +1,60 @@
+/* libs/graphics/ports/SkFontHost_fontconfig_impl.h
+**
+** Copyright 2009, Google Inc.
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+/* The SkFontHost_fontconfig code requires an implementation of an abstact
+ * fontconfig interface. We do this because sometimes fontconfig is not
+ * directly availible and this provides an ability to change the fontconfig
+ * implementation at run-time.
+ */
+
+#ifndef FontConfigInterface_DEFINED
+#define FontConfigInterface_DEFINED
+
+#include <string>
+
+class FontConfigInterface {
+  public:
+    virtual ~FontConfigInterface() { }
+
+    /** Performs config match
+     *
+     *  @param result_family (output) on success, the resulting family name.
+     *  @param result_fileid (output) on success, the resulting file id.
+     *  @param fileid_valid if true, then |fileid| is valid
+     *  @param fileid the fileid (as returned by this function) which we are
+     *    trying to match.
+     *  @param family (optional) the family of the font that we are trying to
+     *    match.
+     *  @param is_bold (optional, set to -1 to ignore)
+     *  @param is_italic (optional, set to -1 to ignore)
+     *  @return true iff successful.
+     */
+    virtual bool Match(
+          std::string* result_family,
+          unsigned* result_fileid,
+          bool fileid_valid,
+          unsigned fileid,
+          const std::string& family,
+          int is_bold,
+          int is_italic) = 0;
+
+    /** Open a font file given the fileid as returned by Match
+     */
+    virtual int Open(unsigned fileid) = 0;
+};
+
+#endif  // FontConfigInterface_DEFINED