Improve profile processing

- allow file descriptors in addition to file names for profiles
- fix some minor issues (wrong comparison signs, unhandled errors)
- added gtests for profile_compilation_info, profile_assistant
and compiler_driver

Bug: 26080105
Change-Id: I136039fa1f25858399000049e48b01eafae54eb1
diff --git a/runtime/base/scoped_flock.h b/runtime/base/scoped_flock.h
index 08612e3..cc22056 100644
--- a/runtime/base/scoped_flock.h
+++ b/runtime/base/scoped_flock.h
@@ -32,10 +32,15 @@
   // Attempts to acquire an exclusive file lock (see flock(2)) on the file
   // at filename, and blocks until it can do so.
   //
-  // Returns true if the lock could be acquired, or false if an error
-  // occurred. It is an error if the file does not exist, or if its inode
-  // changed (usually due to a new file being created at the same path)
-  // between attempts to lock it.
+  // Returns true if the lock could be acquired, or false if an error occurred.
+  // It is an error if its inode changed (usually due to a new file being
+  // created at the same path) between attempts to lock it. In blocking mode,
+  // locking will be retried if the file changed. In non-blocking mode, false
+  // is returned and no attempt is made to re-acquire the lock.
+  //
+  // The file is opened with the provided flags.
+  bool Init(const char* filename, int flags, bool block, std::string* error_msg);
+  // Calls Init(filename, O_CREAT | O_RDWR, true, errror_msg)
   bool Init(const char* filename, std::string* error_msg);
   // Attempt to acquire an exclusive file lock (see flock(2)) on 'file'.
   // Returns true if the lock could be acquired or false if an error
@@ -43,7 +48,7 @@
   bool Init(File* file, std::string* error_msg);
 
   // Returns the (locked) file associated with this instance.
-  File* GetFile();
+  File* GetFile() const;
 
   // Returns whether a file is held.
   bool HasFile();