Teach the network service to clear its disk cache if requested.

mojo/services/network/network_context.cc

Index: mojo/services/network/network_context.cc
diff --git a/mojo/services/network/network_context.cc b/mojo/services/network/network_context.cc
index cd5a8ab828027c2d9b956185e5eed30c494a5f2e..c674fa28f236e4ebc17a58407f6615cbcfa2bc66 100644
--- a/mojo/services/network/network_context.cc
+++ b/mojo/services/network/network_context.cc
@@ -10,6 +10,7 @@
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/files/file_util.h"
 #include "base/path_service.h"
 #include "mojo/common/user_agent.h"
 #include "mojo/services/network/url_loader_impl.h"
@@ -24,6 +25,10 @@ namespace mojo {
 namespace {
 // Logs network information to the specified file.
 const char kLogNetLog[] = "log-net-log";
+
+base::FilePath GetCacheDirectory(const base::FilePath& base_path) {
+  return base_path.Append(FILE_PATH_LITERAL("Cache"));
+}
 }
 
 class NetworkContext::MojoNetLog : public net::NetLog {
@@ -64,6 +69,32 @@ class NetworkContext::MojoNetLog : public net::NetLog {
   DISALLOW_COPY_AND_ASSIGN(MojoNetLog);
 };
 
+// static
+void NetworkContext::ClearCache(const base::FilePath& base_path,
+                                scoped_refptr<base::TaskRunner> task_runner,
+                                const base::Closure& clear_finished_callback) {
+  base::FilePath trash_dir = base_path.Append(FILE_PATH_LITERAL("Trash"));
+  base::CreateDirectory(trash_dir);
+  base::FilePath dest_dir;
+  base::CreateTemporaryDirInDir(trash_dir, "", &dest_dir);
+
+  // Move the current cache directory, if present, into trash.
+  base::FilePath cache_dir = GetCacheDirectory(base_path);
+  if (PathExists(cache_dir)) {
+    base::File::Error error;
+    if (!base::ReplaceFile(cache_dir, dest_dir, &error)) {
+      LOG(ERROR) << "Failed to clear cache content: " << error;
+    }
+  }
+  // Recreate the cache directory.
+  base::CreateDirectory(cache_dir);
+
+  task_runner->PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(base::IgnoreResult(&base::DeleteFile), trash_dir, true),
+      clear_finished_callback);
+}
+
 NetworkContext::NetworkContext(
     scoped_ptr<net::URLRequestContext> url_request_context)
     : net_log_(new MojoNetLog),
@@ -120,7 +151,7 @@ scoped_ptr<net::URLRequestContext> NetworkContext::MakeURLRequestContext(
   // On Android, we store the cache on disk becase we can run only a single
   // instance of the shell at a time.
   cache_params.type = net::URLRequestContextBuilder::HttpCacheParams::DISK;
-  cache_params.path = base_path.Append(FILE_PATH_LITERAL("Cache"));
+  cache_params.path = GetCacheDirectory(base_path);
 #else
   // On desktop, we store the cache in memory so we can run many shells
   // in parallel when running tests, otherwise the network services in each