[js-code-coverage] Helper to setup coverage directory structure

The structure of the coverage directory is internal details of the
DevToolsListener class, extract the structure into a static function
|SetupCoverageStore| to avoid duplication of setup code.

R=noel@chromium.org

	--devtools-code-coverage

Bug: 1113941
Test: browser_tests --gtest_filter=*FilesApp* --devtools-code-coverage
Test: browser_tests --gtest_filter=*DevToolsListener*
Change-Id: Ia5d2a0553eeb791af707734bb5e28d8b3ef1c304
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2528607
Auto-Submit: Ben Reich <benreich@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825750}

chrome/browser/chromeos/file_manager/devtools_listener.cc

@@ -85,6 +85,19 @@ std::string DevToolsListener::HostString(content::DevToolsAgentHost* host,
   return result;
 }
 
+void DevToolsListener::SetupCoverageStore(const base::FilePath& store_path) {
+  if (!base::PathExists(store_path))
+    CHECK(base::CreateDirectory(store_path));
+
+  base::FilePath tests = store_path.AppendASCII("tests");
+  if (!base::PathExists(tests))
+    CHECK(base::CreateDirectory(tests));
+
+  base::FilePath scripts = store_path.AppendASCII("scripts");
+  if (!base::PathExists(scripts))
+    CHECK(base::CreateDirectory(scripts));
+}
+
 void DevToolsListener::Start(content::DevToolsAgentHost* host) {
   std::string enable_runtime = "{\"id\":10,\"method\":\"Runtime.enable\"}";
   SendCommandMessage(host, enable_runtime);

chrome/browser/chromeos/file_manager/devtools_listener.h

@@ -42,6 +42,9 @@ class DevToolsListener : public content::DevToolsAgentHostClient {
   static std::string HostString(content::DevToolsAgentHost* host,
                                 const std::string& prefix = {});
 
+  // Creates coverage output directory and subdirectories.
+  static void SetupCoverageStore(const base::FilePath& store_path);
+
  private:
   // Starts CDP session on host.
   void Start(content::DevToolsAgentHost* host);

chrome/browser/chromeos/file_manager/devtools_listener_browsertest.cc

@@ -78,15 +78,7 @@ class DevToolsListenerBrowserTest : public content::DevToolsAgentHostObserver,
     CHECK(tmp_dir_.CreateUniqueTempDir());
     base::FilePath coverage_store =
         tmp_dir_.GetPath().AppendASCII("devtools_listener_browser_test");
-    CHECK(base::CreateDirectory(coverage_store));
-
-    base::FilePath tests = coverage_store.AppendASCII("tests");
-    if (!base::PathExists(tests))
-      CHECK(base::CreateDirectory(tests));
-
-    base::FilePath scripts = coverage_store.AppendASCII("scripts");
-    if (!base::PathExists(scripts))
-      CHECK(base::CreateDirectory(scripts));
+    DevToolsListener::SetupCoverageStore(coverage_store);
 
     for (auto& agent : devtools_agent_) {
       auto* host = agent.first;

chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc

@@ -1917,15 +1917,7 @@ void FileManagerBrowserTestBase::StartTest() {
   base::FilePath store;
   CHECK(base::PathService::Get(base::DIR_EXE, &store));
   store = store.AppendASCII("devtools_code_coverage");
-  CHECK(base::CreateDirectory(store));
-
-  base::FilePath tests = store.AppendASCII("tests");
-  if (!base::PathExists(tests))
-    CHECK(base::CreateDirectory(tests));
-
-  base::FilePath scripts = store.AppendASCII("scripts");
-  if (!base::PathExists(scripts))
-    CHECK(base::CreateDirectory(scripts));
+  DevToolsListener::SetupCoverageStore(store);
 
   for (auto& agent : devtools_agent_) {
     auto* host = agent.first;