base: "implement" seek time detection for iOS/Android and add more stubs.

base/sys_info_android.cc

Index: base/sys_info_android.cc
diff --git a/base/sys_info_android.cc b/base/sys_info_android.cc
index 245097ffdc092626923e8bcb2f1bbf99e08e51d6..0f2abc57f79e0ab782943826b6cfaf587dc231e7 100644
--- a/base/sys_info_android.cc
+++ b/base/sys_info_android.cc
@@ -155,6 +155,12 @@ int GetDalvikHeapGrowthLimitMB() {
 
 namespace base {
 
+bool SysInfo::HasSeekPenalty(const FilePath& path, bool* has_seek_penalty) {
+  // Find a case where this is incorrect and dbeam@ will buy you a beer.
+  *has_seek_penalty = false;
+  return true;
+}
+
 std::string SysInfo::OperatingSystemName() {
   return "Android";
 }