libnativeloader: Make webviewchromium so file optional

Not all android devices ship with Webview. The requirement of
libwebviewchromium_plat_support.so to be loaded while initializing the
android namespace is therefore liable to cause a crash on devices that
don't support or use Webview. Therefore, this patch makes this
requirement conditional, but enabled by default.

To remove the dependency, device make files should add the following:

TARGET_IGNORE_WEBVIEW_CHROMIUM := true

Bug: 27336841
Bug: 27546414
Change-Id: Iaec1b58236356d981504ea8f716413ea334ca4f4

libnativeloader/Android.mk

@@ -14,6 +14,9 @@ LOCAL_SHARED_LIBRARIES := libnativehelper liblog libcutils
 LOCAL_STATIC_LIBRARIES := libbase
 LOCAL_CLANG := true
 LOCAL_CFLAGS += -Werror -Wall
+ifeq ($(TARGET_IGNORE_WEBVIEW_CHROMIUM), true)
+LOCAL_CFLAGS += -DIGNORE_WEBVIEW_CHROMIUM
+endif
 LOCAL_CPPFLAGS := -std=gnu++14 -fvisibility=hidden
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both
@@ -32,6 +35,9 @@ LOCAL_SHARED_LIBRARIES := libnativehelper liblog libcutils
 LOCAL_STATIC_LIBRARIES := libbase
 LOCAL_CLANG := true
 LOCAL_CFLAGS += -Werror -Wall
+ifeq ($(TARGET_IGNORE_WEBVIEW_CHROMIUM), true)
+LOCAL_CFLAGS += -DIGNORE_WEBVIEW_CHROMIUM
+endif
 LOCAL_CPPFLAGS := -std=gnu++14 -fvisibility=hidden
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both
@@ -49,6 +55,9 @@ LOCAL_SRC_FILES:= $(NATIVE_LOADER_COMMON_SRC_FILES)
 LOCAL_STATIC_LIBRARIES := libnativehelper libcutils liblog libbase
 LOCAL_CLANG := true
 LOCAL_CFLAGS += -Werror -Wall
+ifeq ($(TARGET_IGNORE_WEBVIEW_CHROMIUM), true)
+LOCAL_CFLAGS += -DIGNORE_WEBVIEW_CHROMIUM
+endif
 LOCAL_CPPFLAGS := -std=gnu++14 -fvisibility=hidden
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both

libnativeloader/native_loader.cpp

@@ -55,7 +55,9 @@ static const char* kPublicNativeLibraries = "libandroid.so:"
                                             "libRS.so:"
                                             "libstdc++.so:"
                                             "libvulkan.so:"
+#if !defined(IGNORE_WEBVIEW_CHROMIUM)
                                             "libwebviewchromium_plat_support.so:"
+#endif
                                             "libz.so";
 
 class LibraryNamespaces {