AAPT: ProGuard config for components in main dex.

Create an analogue of "aapt -G" which outputs a proguard configuration
that keeps only components which need to be in the main dex.

Bug: 27383099
Bug: 28425556

Change-Id: Ic18c8c563794ff27a5598a214111d1b446a005f1
(cherry picked from commit 86229cb622fccde8ab8cbe85eead91a34313a708)
diff --git a/tools/aapt/Resource.cpp b/tools/aapt/Resource.cpp
index 18a1943..8e7045b 100644
--- a/tools/aapt/Resource.cpp
+++ b/tools/aapt/Resource.cpp
@@ -2832,7 +2832,7 @@
 }
 
 status_t
-writeProguardForAndroidManifest(ProguardKeepSet* keep, const sp<AaptAssets>& assets)
+writeProguardForAndroidManifest(ProguardKeepSet* keep, const sp<AaptAssets>& assets, bool mainDex)
 {
     status_t err;
     ResXMLTree tree;
@@ -2844,6 +2844,7 @@
     sp<AaptGroup> assGroup;
     sp<AaptFile> assFile;
     String8 pkg;
+    String8 defaultProcess;
 
     // First, look for a package file to parse.  This is required to
     // be able to generate the resource information.
@@ -2900,6 +2901,15 @@
                     addProguardKeepRule(keep, agent, pkg.string(),
                             assFile->getPrintableSource(), tree.getLineNumber());
                 }
+
+                if (mainDex) {
+                    defaultProcess = AaptXml::getAttribute(tree,
+                            "http://schemas.android.com/apk/res/android", "process", &error);
+                    if (error != "") {
+                        fprintf(stderr, "ERROR: %s\n", error.string());
+                        return -1;
+                    }
+                }
             } else if (tag == "instrumentation") {
                 keepTag = true;
             }
@@ -2916,7 +2926,23 @@
                 fprintf(stderr, "ERROR: %s\n", error.string());
                 return -1;
             }
-            if (name.length() > 0) {
+
+            keepTag = name.length() > 0;
+
+            if (keepTag && mainDex) {
+                String8 componentProcess = AaptXml::getAttribute(tree,
+                        "http://schemas.android.com/apk/res/android", "process", &error);
+                if (error != "") {
+                    fprintf(stderr, "ERROR: %s\n", error.string());
+                    return -1;
+                }
+
+                const String8& process =
+                        componentProcess.length() > 0 ? componentProcess : defaultProcess;
+                keepTag = process.length() > 0 && process.find(":") != 0;
+            }
+
+            if (keepTag) {
                 addProguardKeepRule(keep, name, pkg.string(),
                         assFile->getPrintableSource(), tree.getLineNumber());
             }
@@ -3099,30 +3125,12 @@
 }
 
 status_t
-writeProguardFile(Bundle* bundle, const sp<AaptAssets>& assets)
+writeProguardSpec(const char* filename, const ProguardKeepSet& keep, status_t err)
 {
-    status_t err = -1;
-
-    if (!bundle->getProguardFile()) {
-        return NO_ERROR;
-    }
-
-    ProguardKeepSet keep;
-
-    err = writeProguardForAndroidManifest(&keep, assets);
-    if (err < 0) {
-        return err;
-    }
-
-    err = writeProguardForLayouts(&keep, assets);
-    if (err < 0) {
-        return err;
-    }
-
-    FILE* fp = fopen(bundle->getProguardFile(), "w+");
+    FILE* fp = fopen(filename, "w+");
     if (fp == NULL) {
         fprintf(stderr, "ERROR: Unable to open class file %s: %s\n",
-                bundle->getProguardFile(), strerror(errno));
+                filename, strerror(errno));
         return UNKNOWN_ERROR;
     }
 
@@ -3141,6 +3149,49 @@
     return err;
 }
 
+status_t
+writeProguardFile(Bundle* bundle, const sp<AaptAssets>& assets)
+{
+    status_t err = -1;
+
+    if (!bundle->getProguardFile()) {
+        return NO_ERROR;
+    }
+
+    ProguardKeepSet keep;
+
+    err = writeProguardForAndroidManifest(&keep, assets, false);
+    if (err < 0) {
+        return err;
+    }
+
+    err = writeProguardForLayouts(&keep, assets);
+    if (err < 0) {
+        return err;
+    }
+
+    return writeProguardSpec(bundle->getProguardFile(), keep, err);
+}
+
+status_t
+writeMainDexProguardFile(Bundle* bundle, const sp<AaptAssets>& assets)
+{
+    status_t err = -1;
+
+    if (!bundle->getMainDexProguardFile()) {
+        return NO_ERROR;
+    }
+
+    ProguardKeepSet keep;
+
+    err = writeProguardForAndroidManifest(&keep, assets, true);
+    if (err < 0) {
+        return err;
+    }
+
+    return writeProguardSpec(bundle->getMainDexProguardFile(), keep, err);
+}
+
 // Loops through the string paths and writes them to the file pointer
 // Each file path is written on its own line with a terminating backslash.
 status_t writePathsToFile(const sp<FilePathStore>& files, FILE* fp)