Use checked in keystore to sign debug apks

build/android/ant/sdk-targets.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!--
   Copyright (c) 2012 The Chromium Authors. All rights reserved.
   Use of this source code is governed by a BSD-style license that can be
   found in the LICENSE file.
 -->
 <project name="chrome_sdk_overrides" >
   <!--
     Redefinition of targets used by SDK tools.
     Supported version: SDK tools revision 20.
@@ skipping 76 matching lines @@
                 outdir="${out.absolute.dir}/classes"
                 verbosity="${verbosity}">
               <filter excludes="${emma.default.filter}"/>
               <filter value="${emma.filter}"/>
             </instr>
           </emma>
         </then>
       </if>
     </do-only-if-manifest-hasCode>
   </target>
+
+  <!--
+    For debug builds, the Android SDK tools create a key in ~/.android and sign the build with it.
+    This has caused all kinds of issues. Instead, the debug build should be signed with a key in
+    build/android/ant. The SDK tools do not provide any support for overriding that behavior and so
+    instead one must use the hack below.
+  -->
+
+  <!-- Disables automatic signing. -->
+  <property name="build.is.signing.debug" value="false"/>
+
+  <!-- TODO(cjhopman): Remove this property when all gyp files define the CHROMIUM_SRC property. -->
+  <property name="CHROMIUM_SRC" value="${PRODUCT_DIR}/../.." />
+
+  <property name="key.store" value="${CHROMIUM_SRC}/build/android/ant/chromium-debug.keystore"/>
+  <property name="key.store.password" value="chromium"/>
+  <property name="key.alias" value="chromiumdebugkey"/>
+  <property name="key.alias.password" value="chromium"/>
+
+  <!-- SDK tools assume that out.packaged.file is signed and name it "...-unaligned" -->
+  <property name="out.packaged.file"
+    value="${out.dir}/${ant.project.name}-debug-unsigned.apk" />
+  <property name="out.unaligned.file"
+    value="${out.dir}/${ant.project.name}-debug-unaligned.apk" />
+
+  <!-- By default, the SDK tools build only aligns the APK in the -do-debug target. -->
+  <target name="-do-debug"
+      depends="-set-debug-mode, -debug-obfuscation-check, -package, -post-package">
+    <!-- only create apk if *not* a library project -->
+    <do-only-if-not-library elseText="Library project: do not create apk..." >
+      <sequential>
+        <!-- Signs the APK -->
+        <echo level="info">Signing final apk...</echo>
+        <signapk
+          input="${out.packaged.file}"
+          output="${out.unaligned.file}"
+          keystore="${key.store}"
+          storepass="${key.store.password}"
+          alias="${key.alias}"
+          keypass="${key.alias.password}"/>
+
+        <!-- Zip aligns the APK -->
+        <zipalign-helper
+          in.package="${out.unaligned.file}"
+          out.package="${out.final.file}" />
+        <echo level="info">Release Package: ${out.final.file}</echo>
+      </sequential>
+    </do-only-if-not-library>
+    <record-build-info />
+  </target>
 </project>