AW: refactor cache size into a getter method.

No change to behavior, this only moves the value into a getter method
for both code paths.

This moves the cache size to a centrally-determined spot, since we may
want to create more complex logic for the value we set.

R=changwan@chromium.org

Bug: 893318,887538
Test: None
Change-Id: I0e22928bc37a247f165e3913b1e7007fa0d7a1f3
Reviewed-on: https://chromium-review.googlesource.com/c/1357331Reviewed-by: Changwan Ryu <changwan@chromium.org>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613212}

android_webview/browser/aw_content_browser_client.cc

@@ -25,6 +25,7 @@
 #include "android_webview/browser/aw_url_checker_delegate_impl.h"
 #include "android_webview/browser/aw_web_contents_view_delegate.h"
 #include "android_webview/browser/net/aw_url_request_context_getter.h"
+#include "android_webview/browser/net_helpers.h"
 #include "android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.h"
 #include "android_webview/browser/tracing/aw_tracing_delegate.h"
 #include "android_webview/common/aw_content_client.h"
@@ -269,7 +270,7 @@ network::mojom::NetworkContextPtr AwContentBrowserClient::CreateNetworkContext(
   context_params->enable_data_url_support = true;
 
   context_params->http_cache_enabled = true;
-  context_params->http_cache_max_size = 20 * 1024 * 1024;  // 20M
+  context_params->http_cache_max_size = GetHttpCacheSize();
   context_params->http_cache_path = AwBrowserContext::GetCacheDir();
 
   // WebView does not currently support Certificate Transparency.

android_webview/browser/net/aw_url_request_context_getter.cc

@@ -17,6 +17,7 @@
 #include "android_webview/browser/net/aw_url_request_job_factory.h"
 #include "android_webview/browser/net/init_native_callback.h"
 #include "android_webview/browser/net/token_binding_manager.h"
+#include "android_webview/browser/net_helpers.h"
 #include "android_webview/common/aw_content_client.h"
 #include "base/base_paths_android.h"
 #include "base/bind.h"
@@ -324,7 +325,7 @@ void AwURLRequestContextGetter::InitializeURLRequestContext() {
       base::FeatureList::IsEnabled(network::features::kNetworkService)
           ? net::URLRequestContextBuilder::HttpCacheParams::IN_MEMORY
           : net::URLRequestContextBuilder::HttpCacheParams::DISK_SIMPLE;
-  cache_params.max_size = 20 * 1024 * 1024;  // 20M
+  cache_params.max_size = GetHttpCacheSize();
   cache_params.path = cache_path_;
   builder.EnableHttpCache(cache_params);
 

android_webview/browser/net_helpers.cc

@@ -32,4 +32,11 @@ int GetCacheModeForClient(AwContentsIoThreadClient* client) {
   }
 }
 
+int GetHttpCacheSize() {
+  // This currently returns a constant value, but we may consider deciding cache
+  // size dynamically, since Android provides better support on newer versions
+  // (http://crbug.com/893318).
+  return 20 * 1024 * 1024;  // 20M
+}
+
 }  // namespace android_webview

android_webview/browser/net_helpers.h

@@ -14,6 +14,10 @@ class AwContentsIoThreadClient;
 // Gets the net-layer load_flags which reflect |client|'s cache mode.
 int GetCacheModeForClient(AwContentsIoThreadClient* client);
 
+// Determines the desired size for WebView's on-disk HttpCache, measured in
+// Bytes.
+int GetHttpCacheSize();
+
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_NET_HELPERS_H_