android: Raise browser fd limit

Getting too many file open error reports relatively frequently.
Try raising the fd limit to see if things improve.

Changed base implementation to only increase the fd limit. In case
this is used in webview and app has already set the limit above
what we need.

Bug: 842271
Change-Id: I418ea96b4a51fd15e8166d111a191d00153a565c
Reviewed-on: https://chromium-review.googlesource.com/1056070Reviewed-by: Josh Karlin <jkarlin@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Commit-Queue: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558381}

base/process/process_metrics.h

@@ -265,10 +265,11 @@ BASE_EXPORT size_t GetPageSize();
 BASE_EXPORT size_t GetMaxFds();
 
 #if defined(OS_POSIX) && !defined(OS_FUCHSIA)
-// Sets the file descriptor soft limit to |max_descriptors| or the OS hard
-// limit, whichever is lower.
-BASE_EXPORT void SetFdLimit(unsigned int max_descriptors);
-#endif  // defined(OS_POSIX)
+// Increases the file descriptor soft limit to |max_descriptors| or the OS hard
+// limit, whichever is lower. If the limit is already higher than
+// |max_descriptors|, then nothing happens.
+BASE_EXPORT void IncreaseFdLimitTo(unsigned int max_descriptors);
+#endif  // defined(OS_POSIX) && !defined(OS_FUCHSIA)
 
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX) || \
     defined(OS_ANDROID) || defined(OS_AIX) || defined(OS_FUCHSIA)

base/process/process_metrics_ios.cc

@@ -47,7 +47,7 @@ size_t GetMaxFds() {
   return static_cast<size_t>(max_fds);
 }
 
-void SetFdLimit(unsigned int max_descriptors) {
+void IncreaseFdLimitTo(unsigned int max_descriptors) {
   // Unimplemented.
 }
 

base/process/process_metrics_posix.cc

@@ -71,11 +71,12 @@ size_t GetMaxFds() {
   return static_cast<size_t>(max_fds);
 }
 
-
-void SetFdLimit(unsigned int max_descriptors) {
+void IncreaseFdLimitTo(unsigned int max_descriptors) {
   struct rlimit limits;
   if (getrlimit(RLIMIT_NOFILE, &limits) == 0) {
     unsigned int new_limit = max_descriptors;
+    if (max_descriptors <= limits.rlim_cur)
+      return;
     if (limits.rlim_max > 0 && limits.rlim_max < max_descriptors) {
       new_limit = limits.rlim_max;
     }

content/browser/browser_main_loop.cc

@@ -597,7 +597,8 @@ int BrowserMainLoop::EarlyInitialization() {
         command_line->GetSwitchValueASCII(switches::kDisableFeatures));
   }
 
-#if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_CHROMEOS)
+#if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_CHROMEOS) || \
+    defined(OS_ANDROID)
   // We use quite a few file descriptors for our IPC as well as disk the disk
   // cache,and the default limit on the Mac is low (256), so bump it up.
 
@@ -605,8 +606,9 @@ int BrowserMainLoop::EarlyInitialization() {
   // Low soft limits combined with liberal use of file descriptors means power
   // users can easily hit this limit with many open tabs. Bump up the limit to
   // an arbitrarily high number. See https://crbug.com/539567
-  base::SetFdLimit(8192);
-#endif  // defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_CHROMEOS)
+  base::IncreaseFdLimitTo(8192);
+#endif  // defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_CHROMEOS) ||
+        // defined(OS_ANDROID)
 
 #if defined(OS_WIN)
   net::EnsureWinsockInit();

net/disk_cache/disk_cache_perftest.cc

@@ -52,9 +52,9 @@ const int kChunkSize = 32 * 1024;
 // As of 2017-01-12, this is a typical per-tab limit on HTTP connections.
 const int kMaxParallelOperations = 10;
 
-void MaybeSetFdLimit(unsigned int max_descriptors) {
+void MaybeIncreaseFdLimitTo(unsigned int max_descriptors) {
 #if defined(OS_POSIX) && !defined(OS_FUCHSIA)
-  base::SetFdLimit(max_descriptors);
+  base::IncreaseFdLimitTo(max_descriptors);
 #endif
 }
 
@@ -70,20 +70,11 @@ enum class WhatToRead {
 
 class DiskCachePerfTest : public DiskCacheTestWithCache {
  public:
-  DiskCachePerfTest() : saved_fd_limit_(base::GetMaxFds()) {
-    if (saved_fd_limit_ < kFdLimitForCacheTests)
-      MaybeSetFdLimit(kFdLimitForCacheTests);
-  }
-
-  ~DiskCachePerfTest() override {
-    if (saved_fd_limit_ < kFdLimitForCacheTests)
-      MaybeSetFdLimit(saved_fd_limit_);
-  }
+  DiskCachePerfTest() { MaybeIncreaseFdLimitTo(kFdLimitForCacheTests); }
 
   const std::vector<TestEntry>& entries() const { return entries_; }
 
  protected:
-
   // Helper methods for constructing tests.
   bool TimeWrites();
   bool TimeReads(WhatToRead what_to_read, const char* timer_message);
@@ -104,9 +95,6 @@ class DiskCachePerfTest : public DiskCacheTestWithCache {
   const size_t kFdLimitForCacheTests = 8192;
 
   std::vector<TestEntry> entries_;
-
- private:
-  const size_t saved_fd_limit_;
 };
 
 class WriteHandler {