Build metrics_dump tool in Android.

Replace Makefile with Android.bp.
Remove duplication of protos in proto directory.

Since we are now building the metrics_dump tool
under Android, use frameworks metrics.proto
directly. Also, reference cdm's wv_metrics.proto
from the cdm directory instead of creating a
subset in proto directory.

bug: 161783052
bug: 170607430

Test: build
  m -j128 metrics_dump
Test: metrics_dump [bugreport from adt-3-r.zip]
Test: metrics_dump [bugreport from sabrina-q.gz]
Test: metrics_dump --widevine [adb shell dumpsys media.metrics output]
Change-Id: I82c7e723453ac2a6335cb2bb732a376d535b9ea3

libwvdrmengine/tools/metrics_dump/include/parse_metrics.h

@@ -0,0 +1,56 @@
+// Copyright 2020 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+//
+// Take a line as input, parse the metrics, and returns MediaMetrics
+// structure as output.
+
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace metrics_dump {
+
+// This is the order of metrics prior to R release, do not change.
+// We use this to index into a vector of tokens to retrieve metrics.
+typedef enum {
+  kIndexQ,
+  kVersionQ,
+  kComponentQ,
+  kSessionQ,
+  kUidQ,
+  kPackageQ,
+  kPackageVersionQ,
+  kPidQ,
+  kFinalizedQ,
+  kTimestampQ,
+  kItemCountQ,
+  // kPropertiesQ serves as a sentinel to indicate properties follow
+  kPropertiesQ,
+} QMediaMetricsItems;
+
+// This is the order of metrics since R release, do not change.
+// We use this to index into a vector of tokens to retrieve metrics.
+typedef enum {
+  kIndexR,
+  kComponentR,
+  kTimestampR,
+  kPackageR,
+  kPidR,
+  kUidR,
+  // kPropertiesR serves as a sentinel to indicate properties follow
+  kPropertiesR,
+} RMediaMetricsItems;
+
+typedef struct {
+  std::string component, finalized, index, item_count;
+  std::string package, package_version, pid, session;
+  std::string timestamp, version, uid;
+  std::vector<std::pair<std::string, std::string>> properties;
+} MediaMetrics;
+
+bool is_q_metrics(const std::string &line);
+void parse_metrics(const std::string& line, MediaMetrics* metrics);
+void to_lower(std::string& lower);
+
+};  // namespace metrics_dump