Remove shim classes etc. that were needed to move Android Loader

Also those needed to move the Trace classes to base, and tidy
up the other TODOs left over from these moves.

Depends on:
https://codereview.chromium.org/141223002 and
https://chrome-internal-review.googlesource.com/#/c/153179

BUG=225101

Review URL: https://codereview.chromium.org/152663002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@250479 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/findbugs_filter/findbugs_known_bugs.txt

@@ -1,5 +1,3 @@
-H B Nm: The class name org.chromium.base.library_loader.ProcessInitException shadows the simple name of the superclass org.chromium.content.common.ProcessInitException  At ProcessInitException.java
-H B Nm: The class name org.chromium.content.app.LibraryLoader shadows the simple name of the superclass org.chromium.base.library_loader.LibraryLoader  At LibraryLoader.java
 H C EC: Using pointer equality to compare a JavaBridgeCoercionTest$CustomType with a JavaBridgeCoercionTest$CustomType2 in org.chromium.content.browser.JavaBridgeCoercionTest.testPassJavaObject()  At JavaBridgeCoercionTest.java
 H P Bx: Boxing/unboxing to parse a primitive org.chromium.content.browser.ViewportTest.evaluateIntegerValue(String)  At ViewportTest.java
 M B RV: Exceptional return value of java.io.File.delete() ignored in org.chromium.base.test.util.TestFileUtil.deleteFile(String)  At TestFileUtil.java

java_apk.gypi

@@ -123,9 +123,6 @@
       'variables': {
         'native_lib_target%': '',
         'native_lib_version_name%': '',
-        # TODO (aberent) remove use_content_linker once downstream Android has
-        # been switched to use_chromium_linker.
-        'use_content_linker%': 0,
         'use_chromium_linker%' : 0,
         'enable_chromium_linker_tests%': 0,
         'is_test_apk%': 0,
@@ -150,7 +147,6 @@
     },
     'native_lib_target%': '',
     'native_lib_version_name%': '',
-    'use_content_linker%': 0,
     'use_chromium_linker%' : 0,
     'enable_chromium_linker_tests%': 0,
     'emma_instrument': '<(emma_instrument)',
@@ -186,7 +182,7 @@
         '<(DEPTH)/build/android/setup.gyp:copy_system_libraries',
       ],
     }],
-    ['use_content_linker == 1 or use_chromium_linker == 1', {
+    ['use_chromium_linker == 1', {
       'dependencies': [
         '<(DEPTH)/base/base.gyp:chromium_android_linker',
       ],
@@ -218,7 +214,7 @@
         {
           'variables': {
             'conditions': [
-              ['use_content_linker == 1 or use_chromium_linker == 1', {
+              ['use_chromium_linker == 1', {
                 'variables': {
                   'linker_input_libraries': [
                     '<(SHARED_LIB_DIR)/libchromium_android_linker.>(android_product_extension)',
@@ -262,7 +258,7 @@
           'action_name': 'native_libraries_<(_target_name)',
           'variables': {
             'conditions': [
-              ['use_content_linker == 1 or use_chromium_linker == 1', {
+              ['use_chromium_linker == 1', {
                 'variables': {
                   'linker_gcc_preprocess_defines': [
                     '--defines', 'ENABLE_CHROMIUM_LINKER',