Android: Add chrome-specific dynamic linker.

third_party/crazy_linker/crazy_linker/README.TXT

Index: third_party/crazy_linker/crazy_linker/README.TXT
diff --git a/third_party/crazy_linker/crazy_linker/README.TXT b/third_party/crazy_linker/crazy_linker/README.TXT
new file mode 100644
index 0000000000000000000000000000000000000000..1ef51407e011c9f0b7fcd263409570b19a392fbe
--- /dev/null
+++ b/third_party/crazy_linker/crazy_linker/README.TXT
@@ -0,0 +1,54 @@
+A custom dynamic linker for Android programs that adds a few interesting
+features compared to /system/bin/linker:
+
+  - Supports loading a library at an explicit (page-aligned) memory
+    address. The system linker always randomizes the address.
+
+  - Supports loading a library from an explicit (page-aligned) file
+    offset. This can be useful to load a library directly from an .apk,
+    provided that it is uncompressed and at a page-aligned offset.
+
+  - Support changing the library search path. The system linker, when used
+    inside Android applications, is limited to the value of LD_LIBRARY_PATH
+    at boot time, that only looks into system directories, not application
+    ones.
+
+    This linker allows the client to add application paths before the
+    default system ones, this has two benefits:
+
+      - Library dependencies are loaded automatically in the right order.
+
+      - Libraries from the application paths are favored over system ones.
+        This avoids conflicts when one of your application's libraries
+        has the same name than a system one (which happends randomly
+        on certain devices due to system application bundling).
+
+  - Support any number of shared libraries. On older Android platforms,
+    the system linker will refuse to load more than 64 or 128 libraries
+    in a single process (Note: Fixed in Android 4.3).
+
+  - Support sharing of RELRO sections. When two processes load the same
+    library at exactly the same address, the content of its RELRO section
+    is identical. By default, each instance uses private RAM pages to host
+    it, but it is possible to use a single ashmem region to share the same
+    data instead.
+
+See include/crazy_linker.h for the API and its documentation.
+
+A few notes:
+
+  - The crazy linker will always use the system linker to load NDK-exposed
+    system libraries (e.g. liblog.so and others). This avoids having two
+    instances of the same library in the same process, and correctly
+    resolving any symbols from system libraries.
+
+  - Any library loaded by the crazy linker, and which uses functions of
+    libdl.so will continue to work. However, calls to dlopen(), dlsym(),
+    et al will be redirected to the crazy linker's own wrappers.
+
+    This ensures that if a library is loaded by the crazy linker, any of
+    its dependencies will be loaded by it too.
+
+BUGS & TODO:
+  - Libraries loaded by the crazy linker are not automatically closed when
+    the process exits.