Initialize FontConfigIPC when zygote is disabled so font fallback works.

content/browser/linux_ipc_browsertest.cc

+// Copyright 2017 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.
+
+#include <map>
+#include <set>
+#include <string>
+
+#include "base/command_line.h"
+#include "base/macros.h"
+#include "content/browser/renderer_host/sandbox_ipc_linux.h"
+#include "content/public/common/content_switches.h"
+#include "content/public/test/content_browser_test.h"
+#include "content/public/test/content_browser_test_utils.h"
+#include "testing/gmock/include/gmock/gmock-matchers.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/test/fontconfig_util_linux.h"
+
+namespace content {
+
+class LinuxIPCBrowserTest : public ContentBrowserTest,
+                            public SandboxIPCHandler::TestObserver,
+                            public testing::WithParamInterface<std::string> {
+ public:
+  LinuxIPCBrowserTest() {
+    SetUpFontConfigForTest();
+    SandboxIPCHandler::SetObserverForTests(this);
+  }
+  ~LinuxIPCBrowserTest() override {}
+
+ protected:
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    ContentBrowserTest::SetUpCommandLine(command_line);
+    if (GetParam() == "no-zygote") {
+      command_line->AppendSwitch(switches::kNoZygote);
+      command_line->AppendSwitch(switches::kNoSandbox);
+    }
+  }
+
+  // Override the system fontconfig configuration with a test configuration so
+  // that the tested font fallback will work the same across systems.
+  void SetUpFontConfigForTest() {
+    gfx::SetUpFontconfig();
+    for (size_t i = 0; i < gfx::kNumSystemFontsForFontconfig; ++i) {
+      gfx::LoadFontIntoFontconfig(
+          base::FilePath(gfx::kSystemFontsForFontconfig[i]));
+    }
+  }
+
+  void OnFontOpen(int id) override { opened_fonts.insert(font_names[id]); };
+
+  void OnGetFallbackFontForChar(UChar32 c, std::string name, int id) override {
+    fallback_fonts[c] = name;
+    font_names[id] = name;
+  }
+
+  std::map<UChar32, std::string> fallback_fonts;
+  std::map<int, std::string> font_names;
+  std::set<std::string> opened_fonts;
+
+  DISALLOW_COPY_AND_ASSIGN(LinuxIPCBrowserTest);
+};
+
+// Tests that Linux IPC font fallback code runs round-trip when Zygote is
+// disabled. It doesn't care what font is chosen, just that the IPC messages are
+// flowing. This test assumes that U+65E5 (CJK "Sun" character) will trigger the
+// font fallback codepath.
+IN_PROC_BROWSER_TEST_P(LinuxIPCBrowserTest, FontFallbackIPCWorks) {
+  GURL test_url = GetTestUrl("font", "font_fallback.html");
+  EXPECT_TRUE(NavigateToURL(shell(), test_url));
+  EXPECT_THAT(fallback_fonts[U'\U000065E5'], testing::Ne(""));
+  EXPECT_THAT(opened_fonts, testing::Contains(fallback_fonts[U'\U000065E5']));
+}
+
+INSTANTIATE_TEST_CASE_P(LinuxIPCBrowserTest,
+                        LinuxIPCBrowserTest,
+                        ::testing::Values("zygote", "no-zygote"));
+
+}  // namespace